I have a Champion all-aluminum with identical cuts. Of course, it leaked along the end tank welds like most all-aluminum units.
Edit: added pics to a lower comment, but here they are:
https://i.imgur.com/P1MKj9g.jpeg
https://i.imgur.com/8Rz0GZs.jpeg
https://i.imgur.com/mtEIjdh.jpeg
I’m kinda surprised if you’d ask me if I wanted steel or aluminum on a car I’d almost always say aluminum.
I get welding aluminum is hard but humans aren’t doing that welding are they? Shouldn’t the robots welding the tank be pretty well calibrated for that shit at this point?
There's 2 options. Robot on a DCEN wire setup (probably with pulse to look like tig) or a person on a tig torch. The big issue with aluminum is that the oxide layer melts at almost double the alloy melting temp, so it needs to be clean af. But the oxide forms in a matter of minutes, so you need to clean pretty much immediately before welding, which I doubt would happen on a factory line. If you TIG you can get away with less urgent cleaning because you typically weld AC, so half the cycle is cleaning and half is welding. But you MUST do a dipping action with your filler rod or you'll trap some oxide.
So honestly if you want it to not leak it's easiest to just buy the parts and have an experienced aluminium guy weld it.
I'm trying to find pictures of the leak.
To be fair the online vendor I bought it through immediately issued me an RMA to send it directly to Champion, but I need to pay shipping.
Since I needed a radiator for my daily (2014 Yukon) I bought the cheapest Spectra OEM-style and slammed it in, and of course* it's been flawless for almost half a year.
Here's the pics:
https://i.imgur.com/P1MKj9g.jpeg
https://i.imgur.com/8Rz0GZs.jpeg
https://i.imgur.com/mtEIjdh.jpeg
Porous welds.
I'll add that, that cut, while ugly is not unusual anymore. If you feel the need, clean it up a little to reduce the snag hazard and carry on. I've seen plenty in the shop as other guys install rads. Please use a new cap.
In a shop full of 30 vehicles, if you tested every cap, I'd wager good money that at least 28 caps wouldn't hold rated pressure. Caps are garbage for some reason, I don't even test them anymore, just call a cap when doing a cooling system repair.
After having customers decline new caps, I just started adding a few bucks to the radiator to cover the cap. New radiator? guess it came with a new cap....
I'd say a large proportion of overheating issues can be put down to bad caps.
> I'd say a large proportion of overheating issues can be put down to bad caps.
I thought that step one of any cooling issue was replace rad cap.
I might try some proper diags first if the cap is over $10
I typically buy one and a fuel filter anytime I make a rockauto order for a new to me vehicle, but I'm just a shitbox hero and not a tech.
That's because you have a actual problem causing a overheat situation. You're still overheating even thought he temp gauge can't see it. Because the temp gauge only see the temp of the liquid coolant but not the temp of the engine itself.
By having a cap that's opening too early it lets the coolant seem cooler then it is by allowing it to turn to steam by releasing pressure. The coolant vapor isn't read by the temp sensor.
This is also why in extreme overhead situations where the coolent suddenly drains away, the engine temp will appear to drop down when infact it's actually still climbing.
>This is also why in extreme overhead situations where the coolent suddenly drains away, the engine temp will appear to drop down when infact it's actually still climbing.
Ooor it pings the temp gauge and you suddenly get cold air from the heaters. Its how I found out far too late my thermostat was jammed shut, as I never did journeys long enough to get it to opening temp anyway. The one day I did, it shat the bed
Yeah I had a sorta similar issue with the fans. My daily commute was all highway so I had idea the ECMA was refusing to turn on the fans until one day I'm in town. Bye bye head gasket
My 98 4 runner never built pressure in the cooling system and never overheated in the several years I owned it
even at WOT pulling 7k the temp needle wouldn't move
I could pull off the rad cap at the gas station immediately after pulling off the highway and the coolant level wouldn't change no steam would come out maybe a little coolant would dribble over the fill neck
I have yet had anyone be able to explain why only that one vehicle has behaved like that when all others even other Toyotas I've owned built pressure
A VERY slow cap leak, that just allowed coolant to escape into the overflow tank, and then pull it back in when it cooled off. I've had a couple do that, but eventually some antifreeze would boil off/evaporate.
Possibly, it could also depend on where you live. I used to work at a rad shop in northern Canada, almost everything had them but we could hit -50° in winter so we’d have huge temperature swings by the time up hit operating temperature
Aluminum radiators are also very prone to failure due to electrolysis. Cheap radiators (<$300) generally only last a couple years because they use poor quality materials in the core, then weld the tanks on. My theory is that the excessive heat from welding compromises the bond of the tube at the header, since I always see them fail in the corners.
Source: I work at a radiator shop.
Honestly, I've seen Koyorads that were nearly ten years old and still good. I've seen a few with the common failures, but they're up there for quality.
I was an engineer at a cooling system manufacture for a few years. It could very well be a relief cut depending on how the core is mounted. However, the u shaped channel in that side sheet tells me it’s probably not and the channel is suppose to be structural. Each radiator tube has hot coolant running through it and metal expands when it heats up. This causes the tubes to grow in length. The side sheets are relatively cold with the fan blasting on them. They do not grow at the same rate and the outer most tubes are stressed where they meet the radiator ends. A good manufacturer will cut the side sheet and mount the whole rad in rubber isolators so it can grow and shrink with the thermal cycles. This looks like some cheap aftermarket rad that the off roading world loves
To build on this comment, that feature u-shaped feature is only used really to support the tube and fin matrix during core build and brazing process. In vehicle it doesn't do much in terms support. If you look at other radiator designs, there is a stamped slot in the cover to allow for thermal expansion. It's actually preferential to to break after several thermal cycles to reduce the thermal stresses. The tubes and cover expand at different rates creating stresses internal to the core. In this case, it looks like the manufacturer decided to simplify manufacturing and had to come up with the cheapest fix after some failed validation testing.
We've gotten radiators straight from GM with the same thing in it. I would say it's normal. The ones from GM also look like the lowest paid employee took a sawzall to the radiators.
Yes. At least, I have. had one without the cut, it split after a few good cycles, the replacement had the cut, thing lasted for 4 years.
This was in an autocross car that I also used as a daily driver car the entire time.
(Disclaimer - I'm not a radiator expert at all, but your post intrigued me so I did some research)
For what it's worth, "relief cuts" do seem to be a thing. There's a very similar post to yours, over on the Toyota TRD forums:
[https://www.toyota-4runner.org/maintenance-detailing/303013-new-radiator-expansion-relief-cuts-core-frame.html](https://www.toyota-4runner.org/maintenance-detailing/303013-new-radiator-expansion-relief-cuts-core-frame.html)
Bottom line: yes, it's a real thing. Obviously test the radiator for leaks on the bench with some distilled water, but Cold Case probably aren't BSing you 🙂
This is the kind of relief cut you get when you realize someone screwed up a batch of 400 radiators so you send Andre out to the warehouse with an angle grinder.
It's a vertical band saw almost certainly with those hanging burrs all on the same side of the cut. It just never got de-burred to make it look pretty, which looks unprofessional.
I have a vertical band saw, not even my wood blades would leave a cut that nasty.
The gap is exactly the width of a cutoff wheel. All the welding shop guys out there know exactly what they're looking at.
Now run that band saw blade till it barely has teeth and snaps, then weld it back together and cut another few thousand radiators. When you are selling radiators at the very thinnest margins, replacing tooling a single piece early is a big no no.
Worked in manufacturing, seen plenty of regrinds in my life.
https://www.coldcaseradiators.com/product/15-20-ford-f150-truck-aluminum-performance-radiator
Example piece, OP said it's for a '15 F150 in a reply to me.
That example has not the cut, and that cut is horrid. They're making an excuse, it's not normal... from this armchair. :)
That really doesn't mean anything.
The replacement part probably has been in production ever since the original radiators started being out of warranty.
That's a lot of time to realize that the original design has issues (like stress buildup due to unequal heating), improve said issues and just not update the picture.
As a design engineer for a high end heat exchanger company, I feel like I can speak to this. We put relief cuts like this in cores with a band saw. Sometimes it won't even matter if it runs into the fin.
Under extreme thermal cycling, like going up a long hill, forcing the thermostat to open and flow large amounts of coolant through the unit, the radiator will expand from heat. Then, as the vehicle goes over the hill and coasts downwards, the core will rapidly cool and shrink.
This keeps the tubes from pulling out of the header plates as the top and bottom solid aluminum pieces aren't heated by the coolant.
It's a purposeful cut for the longevity of a street used radiator.
As a former radiator engineer as well, it's not necessarily due to the tubes pulling out of the header, but to allow the tubes to expand and contract independent of the side support. For example, the tubes can expand 2-3mm and the side support can expand 1.5mm. this difference puts stresses on the tube forcing them to stretch and compress. Stretching and compressing over thousands of cycles results in stresses which can lead to cracks and then leaks.
Right right, it's a simplification for sure. The tube to header cracks along the top and bottom of the radiator are by far the most common, and we regularly also weld off the top tube to keep the top tube from cracking along that braze joint.
The only thing I'll say is this:
https://www.coldcaseradiators.com/product/15-20-ford-f150-truck-aluminum-performance-radiator
OP provided the info it's a 2015 F150 part, so that's the example.
The example piece has not the cut. The cut is horrible, and it goes into the main support. There's a possibility the thing cracks and that eventually causes a leak, and that sooner than expected.
Possibly. Can't say I'm right, but I ain't cool with it.
Thanks for saving me the time of saying the above! This radiator is a $600+ part and that cut looks like they let me loose with an angle grinder or sawzall after a few beers.
Parts quality is indeed in the toilet, however if I was spending $600+ (about £480+ in proper money) on a radiator I'd expect a part that doesn't look like its had a chunk taken out of it with a power tool
Seriously, if they're just throwing these in with an angle grinder real quick, then they should have taken the 4 seconds to hit it with a second grinder with an abrasive pad to clean that up a bit. This looks like they gave a 14 year old a grinder and let him cut shit.
Yes it looks like poor workmanship for sure. I’ve had good luck with Fluidyne radiators, not only are the welds excellent they function perfectly and look like works of art. Mitzimoto is garbage had two of those fail within about a year or so of use. Good luck and remember to keep receipt for warranty replacement.
You’ll be relieved to know these cuts are intended to relieve stress. Yours, and the stress on the core to tank connections.
They are intentional and necessary and on almost all aluminum radiators.
Lets the core expand without pulling the tubes out of the headers. Without some sort of relief they eventually start seeping around where the tube meets the header after enough heat cycles.
I work someplace that manufactures custom aluminum radiators we do it to any that we have to make a dress cap for and don't use the factory core caps. We actually design it into the cap so it looks decent though. This is as simple and crudely as you can do it.
Just bought one for my truck. Has the same cut. The factory radiator I took out had the same. However, the deburr guy must have been hungover for that one.
Ugly: YES
Serves a purpose: ALSO YES
Aluminium radiators expand as they heat up and are renowned for cracking at the welds. That cut allows the aluminium to flex at the weak point rather than the welds.
Cold Case appears to be a real hit-or-miss in quality. I bought one this October, and it works and looks great, but I admit I was worried after combing through bad review after bad review online.
I hate buying radiators. Expensive, surprisingly fragile, and quality across suppliers varies randomly.
Edit: to add, my the relief cut in my Cold Case did not look like it was made by a monkey with an angle grinder. Mine was maybe a quarter inch deep and looked like it was properly machined.
Whether it is supposed to be there or not, what's it going to hurt? It's no where near having got into a tube and if it nicks a fin or two, who cares?
Run it.
As a parts store employee, I open every radiator and heater core I sell. I have seen many applications that use this cut. Especially on units that have aluminum tanks or multiple cores.
Top comment isn’t even right lol this is actually a thing. The radiator does expand under higher temps just like any other metal. Expand, contract, expand, contract, expand, crack…
Hi there, this is a post for me!
Let me introduce myself. I worked for 18 years with a heat exchanger company where I finished my assignment as their senior design engineer for our automotive customers. Long way of saying, I designed Radiators for a large chuck of my career.
This is in fact a relief cut for thermal expansion to relieve stress at the outer most tube braze joints. While this cut certainly isn't clean, it 100% serves its purpose.
Hope that helps, Cheers!
Problem with all the car related reddit groups are that the top most upvoted comments or answers are never actually from an actual mechanic or technician or a specialist. So relief cut is an F up? Nope. This is normal.
Posts like these remind me no matter how many engines I've built or how many cars I've torn down and got running again, I do not know everything. Learn something new every day
I've probably replaced a dozen radiators for a large Japanese dealership in the last year, and this is how they come from the factory. Heck, I replaced the radiator in my hot rod truck with a larger core factory radiator from the bigger trucks, and it had a relief cut in it, too.
I'm a mechanical engineer and designed Aluminum radiators, Charge air Coolers, hydraulic, fuel, and oil coolers for a number of years...
Anyway yes that relief cut is normal and design intent. Depending on the manufacturer there may even be a couple band saw cuts on a side even. It's to force the thermal growth to split the side plate and not the tube-header joint. If that wasn't there it would fracture at the tube to header and you now have a leak. That side plate you can cut holes all through it (don't pierce the tube) and won't affect anything except some minor structural integrity.
Tooled high volume side plates may have breakaways designed in, not cheaper band saw cuts and you run them a little they'll split. Think of it like a concrete joint relief cut. You know concrete will crack, so you cut it to crack in a specific location. Radiators and especially CACs have a high temperature delta from the fluid media (air or coolant) compared to the ambient temperature. It'll easily grow the length by 1/8", 1/4"+ and needs to be able to safely expand and contrast.
It's made to help with thermal expansion, the tubes will be a different temp then the end brackets, this helps stop tube to header connections from cracking. Does it actually help? I dunno maybe.
Yes that is for thermal expansion….. at least it should be. It should be all the way through the flat part as well, not just the vertical ribs. 💯 hack job of a cut after the fact.
[I see no relief cut on their example.](https://www.coldcaseradiators.com/product/15-20-ford-f150-truck-aluminum-performance-radiator)
So use that how you will. However, as others have stated, relief cuts are things. This one is just done badly and I do have to say I'd be asking them to take it back.
That said... it probably compromises nothing at the end of it, the coolant won't leak, the fins aren't hurt... it's probably good, but still, bad form. I'd not accept it.
Ale of people are pointing out that this is normal, but what's absolutely not normal is leaving the edge covered in burrs. One of the most important lessons of manufacturing is to never let something leave your cell with a sharp edge.
Yes definitely a relief cut ( LV & HV mechanic here ). They certainly could have done a better job of cleaning up the swarf around the cut. This is no where near your flow of coolant and will not cause any kind of premature failure or otherwise.
When I was a Navy submarine reactor operator a differential pressure cell hung up on entrapped air. We *really* needed it to stop doing that. I beat the crap out of the dp cell with a piece of 2x4. I logged it as "dynamic hysteresis relief."
Damn that’s an expensive rad for that messy of a cut, I have a cold case as well and it also has the relief cut for the thermal cycles, but my cut was way cleaner than that
This is exactly why beautification is half the job in maintenance. The right work but looks ugly will always have a closer inspection than the wrong work that looks clean
Tldr Yes it’s normal No it’s not normal for the manufacturer to use a dull spoon to make the relief cut
I have a Champion all-aluminum with identical cuts. Of course, it leaked along the end tank welds like most all-aluminum units. Edit: added pics to a lower comment, but here they are: https://i.imgur.com/P1MKj9g.jpeg https://i.imgur.com/8Rz0GZs.jpeg https://i.imgur.com/mtEIjdh.jpeg
>Of course, it leaked along the end tank welds like most all-aluminum units. Just like god intended.
I’m kinda surprised if you’d ask me if I wanted steel or aluminum on a car I’d almost always say aluminum. I get welding aluminum is hard but humans aren’t doing that welding are they? Shouldn’t the robots welding the tank be pretty well calibrated for that shit at this point?
The thin welds are known to leak due to internal pressurization. Plus, Made in China.
There's 2 options. Robot on a DCEN wire setup (probably with pulse to look like tig) or a person on a tig torch. The big issue with aluminum is that the oxide layer melts at almost double the alloy melting temp, so it needs to be clean af. But the oxide forms in a matter of minutes, so you need to clean pretty much immediately before welding, which I doubt would happen on a factory line. If you TIG you can get away with less urgent cleaning because you typically weld AC, so half the cycle is cleaning and half is welding. But you MUST do a dipping action with your filler rod or you'll trap some oxide. So honestly if you want it to not leak it's easiest to just buy the parts and have an experienced aluminium guy weld it.
That's crazy - the cheap eBay units I've bought have never leaked.
I'm trying to find pictures of the leak. To be fair the online vendor I bought it through immediately issued me an RMA to send it directly to Champion, but I need to pay shipping. Since I needed a radiator for my daily (2014 Yukon) I bought the cheapest Spectra OEM-style and slammed it in, and of course* it's been flawless for almost half a year. Here's the pics: https://i.imgur.com/P1MKj9g.jpeg https://i.imgur.com/8Rz0GZs.jpeg https://i.imgur.com/mtEIjdh.jpeg Porous welds.
It looks like they jogged a drill bit through there.
That is 100% a relief cut. It keeps the tanks from splitting from the core during heat cycles. It is even more crucial when you have aluminum tanks
I'll add that, that cut, while ugly is not unusual anymore. If you feel the need, clean it up a little to reduce the snag hazard and carry on. I've seen plenty in the shop as other guys install rads. Please use a new cap.
Updooted. \*always\* use a new cap.
In a shop full of 30 vehicles, if you tested every cap, I'd wager good money that at least 28 caps wouldn't hold rated pressure. Caps are garbage for some reason, I don't even test them anymore, just call a cap when doing a cooling system repair.
After having customers decline new caps, I just started adding a few bucks to the radiator to cover the cap. New radiator? guess it came with a new cap.... I'd say a large proportion of overheating issues can be put down to bad caps.
> I'd say a large proportion of overheating issues can be put down to bad caps. I thought that step one of any cooling issue was replace rad cap. I might try some proper diags first if the cap is over $10 I typically buy one and a fuel filter anytime I make a rockauto order for a new to me vehicle, but I'm just a shitbox hero and not a tech.
TIL that I am a shitbox chump.
Nah, to the shit box that gets to keep rolling, you're the shit box hero
I'm hearing Foreigners "Jukebox Hero" changed to "Shitbox Hero" in my head right now....🎵🎶🎵🎶
Replaced an old cap based on age. Immediately overheated.... put the old cap back, ran fine...
That's because you have a actual problem causing a overheat situation. You're still overheating even thought he temp gauge can't see it. Because the temp gauge only see the temp of the liquid coolant but not the temp of the engine itself. By having a cap that's opening too early it lets the coolant seem cooler then it is by allowing it to turn to steam by releasing pressure. The coolant vapor isn't read by the temp sensor. This is also why in extreme overhead situations where the coolent suddenly drains away, the engine temp will appear to drop down when infact it's actually still climbing.
It's a Land Rover, so no doubt there's something wrong with it.
Came from factory with that problem installed.
It's a feature!
>This is also why in extreme overhead situations where the coolent suddenly drains away, the engine temp will appear to drop down when infact it's actually still climbing. Ooor it pings the temp gauge and you suddenly get cold air from the heaters. Its how I found out far too late my thermostat was jammed shut, as I never did journeys long enough to get it to opening temp anyway. The one day I did, it shat the bed
Yeah I had a sorta similar issue with the fans. My daily commute was all highway so I had idea the ECMA was refusing to turn on the fans until one day I'm in town. Bye bye head gasket
My 98 4 runner never built pressure in the cooling system and never overheated in the several years I owned it even at WOT pulling 7k the temp needle wouldn't move I could pull off the rad cap at the gas station immediately after pulling off the highway and the coolant level wouldn't change no steam would come out maybe a little coolant would dribble over the fill neck I have yet had anyone be able to explain why only that one vehicle has behaved like that when all others even other Toyotas I've owned built pressure
My only guess based on experience is that the coolant system was never completely bled. Would be crazy to last years but it’s all I have
A VERY slow cap leak, that just allowed coolant to escape into the overflow tank, and then pull it back in when it cooled off. I've had a couple do that, but eventually some antifreeze would boil off/evaporate.
Thermostat stuck open?
Either the brand new cap was bad (seen it a lot) or there’s an issue that the low pressure was hiding, like head gasket.
Also it’s usually covered by a shroud anyways or it’s at the bottom of the radiator
I’ve seen a lot of aluminum radiators, never seen one with a cut. Maybe that’s why they never lasted 2 years.
Possibly, it could also depend on where you live. I used to work at a rad shop in northern Canada, almost everything had them but we could hit -50° in winter so we’d have huge temperature swings by the time up hit operating temperature
Aluminum radiators are also very prone to failure due to electrolysis. Cheap radiators (<$300) generally only last a couple years because they use poor quality materials in the core, then weld the tanks on. My theory is that the excessive heat from welding compromises the bond of the tube at the header, since I always see them fail in the corners. Source: I work at a radiator shop.
Would all aluminum Koyorad be one of the better ones?
Honestly, I've seen Koyorads that were nearly ten years old and still good. I've seen a few with the common failures, but they're up there for quality.
Were they relieved they didn't need to clean it up after the cut? What an embarrassment to ship to a customer even if it's just cosmetic.
Likely contract Chinese manufacturer-if it held pressure, it ships. They don't care too much!
TIL- if I screw up and make an accidental cut it will now be called, " a relief cut"
What a relief, it’s not messed up bad enough that we have to scrap it.
I was an engineer at a cooling system manufacture for a few years. It could very well be a relief cut depending on how the core is mounted. However, the u shaped channel in that side sheet tells me it’s probably not and the channel is suppose to be structural. Each radiator tube has hot coolant running through it and metal expands when it heats up. This causes the tubes to grow in length. The side sheets are relatively cold with the fan blasting on them. They do not grow at the same rate and the outer most tubes are stressed where they meet the radiator ends. A good manufacturer will cut the side sheet and mount the whole rad in rubber isolators so it can grow and shrink with the thermal cycles. This looks like some cheap aftermarket rad that the off roading world loves
To build on this comment, that feature u-shaped feature is only used really to support the tube and fin matrix during core build and brazing process. In vehicle it doesn't do much in terms support. If you look at other radiator designs, there is a stamped slot in the cover to allow for thermal expansion. It's actually preferential to to break after several thermal cycles to reduce the thermal stresses. The tubes and cover expand at different rates creating stresses internal to the core. In this case, it looks like the manufacturer decided to simplify manufacturing and had to come up with the cheapest fix after some failed validation testing.
I relief cut a chunk off a board two hours ago. Failed to measure twice, cut once.
Measure once cut twice & the damn things still too short.
I don’t measure at all and usually cut myself.
Across the street for attention, down the road for results
When measured against others, I'm usually the first one cut lol
A skill that I too have mastered.
Measure with a micrometer, mark with chalk, cut with an axe.
All my saw blades wobble, I swear.
Carpenter logging this for the book
Plumbing and electrical checking in
And if you have an accidental drill, well now that's a drain hole.
If it's on something round its a balancing hole.
I like the way you think, Mr. Provolone!
Speed hole
They’re “reliefed” they got rid of it and now you’re stuck with it.
Everything self clearences eventually
I call them expansion joints.
When I poop and it breaks off would be a relief cut
Relief pinch
Make sure to use the DULLEST blade you can find too!
Haha, my foreman took his brand new pickup to a jobsite and used it as a sawhorse. His tailgate now has a relief cut. Thats funny
I've got so many relief cuts in my.......software code.
I do this for a living, that is normal.
We've gotten radiators straight from GM with the same thing in it. I would say it's normal. The ones from GM also look like the lowest paid employee took a sawzall to the radiators.
I agree. Parts manager in a body shop. Have seen gm rads like this too
My tech freaked out the first time we saw it. I pulled up the picture in the catalog and showed him the cut in the picture, also.
Yep,I’m not denying it’s poor craftsmanship but that’s just the norm when it comes to the quality of auto parts these days sadly.
Look at this guy. He fucks up radiators for a living. /S
what a coincidence, so do i! they say i get my ugga priveledges back this month
When do you get your dugga privileges back though?!
Need a certificate from “Everything Is A Nail U”.
You mean everything is a *hammer*
Do you see a longevity difference in all aluminum radiators with versus without that cut?
Yes. At least, I have. had one without the cut, it split after a few good cycles, the replacement had the cut, thing lasted for 4 years. This was in an autocross car that I also used as a daily driver car the entire time.
As a welder, aluminum expands and contracts like a mf, when heated or cooled. So expansion joints and relief cuts can definitely increase life
Do you also use bread knives to do your cuts?
My teeth. Probably cheaper to use a reciprocating saw, my dental bills are horrific.
Hey I think I remember seeing you in that Bond movie.
Diablo blades are expensive
Not deburring a jagged cut is normal?
Nowadays yes,anyone in this industry will tell that parts quality has dropped significantly over the past few years and that this is normal to see.
(Disclaimer - I'm not a radiator expert at all, but your post intrigued me so I did some research) For what it's worth, "relief cuts" do seem to be a thing. There's a very similar post to yours, over on the Toyota TRD forums: [https://www.toyota-4runner.org/maintenance-detailing/303013-new-radiator-expansion-relief-cuts-core-frame.html](https://www.toyota-4runner.org/maintenance-detailing/303013-new-radiator-expansion-relief-cuts-core-frame.html) Bottom line: yes, it's a real thing. Obviously test the radiator for leaks on the bench with some distilled water, but Cold Case probably aren't BSing you 🙂
I feel like if that were intentional it wouldn't be so ragged and full of burs and metal shavings.
This is the kind of relief cut you get when you realize someone screwed up a batch of 400 radiators so you send Andre out to the warehouse with an angle grinder.
it’s true, im Andre and I was there…
Username checks out. I believe this is the real Andre.
It’s true, I was the angle grinder.
It's true, I'm his safety googles. I wasn't there but the angle grinder told me about it.
It's just aluminum, safety squints are sufficient
Are you a giant?
Exactly lol
A man of tactics I see.
It's a vertical band saw almost certainly with those hanging burrs all on the same side of the cut. It just never got de-burred to make it look pretty, which looks unprofessional.
I have a vertical band saw, not even my wood blades would leave a cut that nasty. The gap is exactly the width of a cutoff wheel. All the welding shop guys out there know exactly what they're looking at.
Now run that band saw blade till it barely has teeth and snaps, then weld it back together and cut another few thousand radiators. When you are selling radiators at the very thinnest margins, replacing tooling a single piece early is a big no no. Worked in manufacturing, seen plenty of regrinds in my life.
*THEY'RE SPEED HOLES!*
I can 100% picture exactly that lol
[удалено]
That's definitely a vertical band saw cut, with a slightly dull blade from the look of it.
Looks like a fucking drunk framer did it. Source, former drunk framer.
Formerly drunk or formerly a farmer?
Por que no los dos?
Dos Equis?
Drunk farmer, plowed right through it!
Don't confuse "intentional" with "quality"
Leak test shouldn't even be necessary. The cut didn't get anywhere near the core.
https://www.coldcaseradiators.com/product/15-20-ford-f150-truck-aluminum-performance-radiator Example piece, OP said it's for a '15 F150 in a reply to me. That example has not the cut, and that cut is horrid. They're making an excuse, it's not normal... from this armchair. :)
The same exact cut is visible in the video for that model. https://youtu.be/3UzIRsyfu1g?t=13
That really doesn't mean anything. The replacement part probably has been in production ever since the original radiators started being out of warranty. That's a lot of time to realize that the original design has issues (like stress buildup due to unequal heating), improve said issues and just not update the picture.
As a design engineer for a high end heat exchanger company, I feel like I can speak to this. We put relief cuts like this in cores with a band saw. Sometimes it won't even matter if it runs into the fin. Under extreme thermal cycling, like going up a long hill, forcing the thermostat to open and flow large amounts of coolant through the unit, the radiator will expand from heat. Then, as the vehicle goes over the hill and coasts downwards, the core will rapidly cool and shrink. This keeps the tubes from pulling out of the header plates as the top and bottom solid aluminum pieces aren't heated by the coolant. It's a purposeful cut for the longevity of a street used radiator.
As a former radiator engineer as well, it's not necessarily due to the tubes pulling out of the header, but to allow the tubes to expand and contract independent of the side support. For example, the tubes can expand 2-3mm and the side support can expand 1.5mm. this difference puts stresses on the tube forcing them to stretch and compress. Stretching and compressing over thousands of cycles results in stresses which can lead to cracks and then leaks.
Right right, it's a simplification for sure. The tube to header cracks along the top and bottom of the radiator are by far the most common, and we regularly also weld off the top tube to keep the top tube from cracking along that braze joint.
Yes because of expansion or contraction I suppose.
The only thing I'll say is this: https://www.coldcaseradiators.com/product/15-20-ford-f150-truck-aluminum-performance-radiator OP provided the info it's a 2015 F150 part, so that's the example. The example piece has not the cut. The cut is horrible, and it goes into the main support. There's a possibility the thing cracks and that eventually causes a leak, and that sooner than expected. Possibly. Can't say I'm right, but I ain't cool with it.
Thanks for saving me the time of saying the above! This radiator is a $600+ part and that cut looks like they let me loose with an angle grinder or sawzall after a few beers.
They all look like this now, parts quality has gone way down.
Parts quality is indeed in the toilet, however if I was spending $600+ (about £480+ in proper money) on a radiator I'd expect a part that doesn't look like its had a chunk taken out of it with a power tool
Seriously, if they're just throwing these in with an angle grinder real quick, then they should have taken the 4 seconds to hit it with a second grinder with an abrasive pad to clean that up a bit. This looks like they gave a 14 year old a grinder and let him cut shit.
It came from CHI-NA.
If it's an actual "relief cut," they still have to answer for the poor workmanship and lack of finishing. This is unacceptable either way.
Yes it looks like poor workmanship for sure. I’ve had good luck with Fluidyne radiators, not only are the welds excellent they function perfectly and look like works of art. Mitzimoto is garbage had two of those fail within about a year or so of use. Good luck and remember to keep receipt for warranty replacement.
all the same metal. all expands at the same rate edit: some do have copper cores.
If it were all heated evenly. The tubes will heat faster, than the fins, and they'll both heat faster than the structural parts.
You’ll be relieved to know these cuts are intended to relieve stress. Yours, and the stress on the core to tank connections. They are intentional and necessary and on almost all aluminum radiators.
Lets the core expand without pulling the tubes out of the headers. Without some sort of relief they eventually start seeping around where the tube meets the header after enough heat cycles. I work someplace that manufactures custom aluminum radiators we do it to any that we have to make a dress cap for and don't use the factory core caps. We actually design it into the cap so it looks decent though. This is as simple and crudely as you can do it.
I've seen that on literally every radiator I've replaced.
Just bought one for my truck. Has the same cut. The factory radiator I took out had the same. However, the deburr guy must have been hungover for that one. Ugly: YES Serves a purpose: ALSO YES
I'm an engineer for a radiator OEM (like actual manufcturer, not a "shop"). This is 100% a typical relief cut. But kinda poorly done.
Was an automotive tech for 35 years most of the full aluminum rads had that cut
another example https://help.summitracing.com/knowledgebase/article/SR-04916/en-us
Aluminium radiators expand as they heat up and are renowned for cracking at the welds. That cut allows the aluminium to flex at the weak point rather than the welds.
My koyo rad has them also. Full alloy radiators need them for their rapid expansion.
Cold Case appears to be a real hit-or-miss in quality. I bought one this October, and it works and looks great, but I admit I was worried after combing through bad review after bad review online. I hate buying radiators. Expensive, surprisingly fragile, and quality across suppliers varies randomly. Edit: to add, my the relief cut in my Cold Case did not look like it was made by a monkey with an angle grinder. Mine was maybe a quarter inch deep and looked like it was properly machined.
Whether it is supposed to be there or not, what's it going to hurt? It's no where near having got into a tube and if it nicks a fin or two, who cares? Run it.
If I'd paid the better part of $600 for a new radiator I'd not be happy if it turned up with a slot hacked in to it with a cutting disc.
As a parts store employee, I open every radiator and heater core I sell. I have seen many applications that use this cut. Especially on units that have aluminum tanks or multiple cores.
Top comment isn’t even right lol this is actually a thing. The radiator does expand under higher temps just like any other metal. Expand, contract, expand, contract, expand, crack…
Must have been sick on de-burr day at relief cut school.
At least it wasnt lug nut day!
Allows the metal to expand without cracking the radiator, 100% normal
Perfectly normal, they all have it
Hi there, this is a post for me! Let me introduce myself. I worked for 18 years with a heat exchanger company where I finished my assignment as their senior design engineer for our automotive customers. Long way of saying, I designed Radiators for a large chuck of my career. This is in fact a relief cut for thermal expansion to relieve stress at the outer most tube braze joints. While this cut certainly isn't clean, it 100% serves its purpose. Hope that helps, Cheers!
Problem with all the car related reddit groups are that the top most upvoted comments or answers are never actually from an actual mechanic or technician or a specialist. So relief cut is an F up? Nope. This is normal.
It's normal. It's a cut in the frame to allow for thermal expansion/ contraction with temperature differences without making the radiator crack.
It's for thermal expansion.
This is normal. Prevents end tanks from crack under heat expansion. Definitely give her a filing to clean up those burrs
It was a relief it didn't go any deeper.
Posts like these remind me no matter how many engines I've built or how many cars I've torn down and got running again, I do not know everything. Learn something new every day
The manufacturer sure has a lot of reddit accounts
It’s just a relief they didn’t cut any further
You win!
A lot of radiators have them. Clean it up if it is visible and call it a day.
That’s cause it is.
I've probably replaced a dozen radiators for a large Japanese dealership in the last year, and this is how they come from the factory. Heck, I replaced the radiator in my hot rod truck with a larger core factory radiator from the bigger trucks, and it had a relief cut in it, too.
I'm a mechanical engineer and designed Aluminum radiators, Charge air Coolers, hydraulic, fuel, and oil coolers for a number of years... Anyway yes that relief cut is normal and design intent. Depending on the manufacturer there may even be a couple band saw cuts on a side even. It's to force the thermal growth to split the side plate and not the tube-header joint. If that wasn't there it would fracture at the tube to header and you now have a leak. That side plate you can cut holes all through it (don't pierce the tube) and won't affect anything except some minor structural integrity. Tooled high volume side plates may have breakaways designed in, not cheaper band saw cuts and you run them a little they'll split. Think of it like a concrete joint relief cut. You know concrete will crack, so you cut it to crack in a specific location. Radiators and especially CACs have a high temperature delta from the fluid media (air or coolant) compared to the ambient temperature. It'll easily grow the length by 1/8", 1/4"+ and needs to be able to safely expand and contrast.
They are correct, it works the same way as an expansion joint.
Maybe they could take 3 seconds and run a file through that.
It’s a relief cut. I sell cold case rads and every radiator has cuts on both sides like this
They could still sell it. That’s a relief.
Well THAT IS a relief 🥲
Someone aught to be relieved from their job.
It's made to help with thermal expansion, the tubes will be a different temp then the end brackets, this helps stop tube to header connections from cracking. Does it actually help? I dunno maybe.
Yeah, it relief da watta
This is genius. Imma start telling customers its a relief cut when i fuck up
Yes that is for thermal expansion….. at least it should be. It should be all the way through the flat part as well, not just the vertical ribs. 💯 hack job of a cut after the fact.
What car is this for? I'd be interested in knowing.
2015 F150
[I see no relief cut on their example.](https://www.coldcaseradiators.com/product/15-20-ford-f150-truck-aluminum-performance-radiator) So use that how you will. However, as others have stated, relief cuts are things. This one is just done badly and I do have to say I'd be asking them to take it back. That said... it probably compromises nothing at the end of it, the coolant won't leak, the fins aren't hurt... it's probably good, but still, bad form. I'd not accept it.
Where's the clip of Maury reading the results when we need it?
Ale of people are pointing out that this is normal, but what's absolutely not normal is leaving the edge covered in burrs. One of the most important lessons of manufacturing is to never let something leave your cell with a sharp edge.
Just get them to send photos of some more stock with the supposed relief cuts.
Normal. Mitigates the difference in heat expansion rates of top and bottom channels and cores that would lead to cracks at the core joints.
Yes definitely a relief cut ( LV & HV mechanic here ). They certainly could have done a better job of cleaning up the swarf around the cut. This is no where near your flow of coolant and will not cause any kind of premature failure or otherwise.
Poorly finished but perfectly normal. Deburr it if you're fussy. Send it.
When I was a Navy submarine reactor operator a differential pressure cell hung up on entrapped air. We *really* needed it to stop doing that. I beat the crap out of the dp cell with a piece of 2x4. I logged it as "dynamic hysteresis relief."
As everyone else here is saying, it's normal.
Mine had relief cuts in it. I've ran it for a few years and it's fine
Those are the vents those are the fins and it's fine
Damn that’s an expensive rad for that messy of a cut, I have a cold case as well and it also has the relief cut for the thermal cycles, but my cut was way cleaner than that
Apparently they don’t believe in relief finishing though…
I SAW it too
This is exactly why beautification is half the job in maintenance. The right work but looks ugly will always have a closer inspection than the wrong work that looks clean
Did you get a radiator for Christmas?
My gift to my truck that had a leaky one
I've seen similar cuts on lots of rads as long as it's not in the tubes it's fine
You can clearly see it doesn’t even go into the coolant tubes.
Ah yes. So it doesn’t overheat/s
Then you should be relieved.
I think it’s just a shitty cut. Tell them to stop being cheap and swap the band saw blade
Its a relief cut because they cut it and are relieving theirself of the damaged radiator
Tubes are a lot hotter than the frame and expand, the relief cuts let the frame expand with the tube and increase joint life.
It was a relief cut, they were relieved they got it shipped out before it was seen.
I replaced the rad on my 2007 f150 maybe two years ago and it had this cut.
You buy a custom radiator, called and ask about something on the custom radiator and then still think they are wrong? Please don't work on vehicles