MK IV Radiator failure

[WBILB]

Yesterday I noticed a slight coolant leak near the upper hose inlet after a spirited drive. Checked and tightened the clamps and then pressurized the system. Sure enough there was a leak at the top of the radiator below the top plate. Removed the radiator and took it to a radiator shop I have used for years. Diagnosis... Top tube split and cannot be repaired, he said it must have overheated (which it absolutely did not). Anyone seen this before? I'm running the FFR radiator with Breeze fan and shroud in a 302SBF and have never seen the coolant temp go over 210? Will most likely replace with a new FFR unit...any thoughts appreciated.
Thanks
Bill

[Bob Cowan]

First time I've heard of that happening.

Overheating causes excess pressure. But so does a blown head gasket. Any other signs of overpressure?

[WBILB]

First time I've heard of that happening.

Overheating causes excess pressure. But so does a blown head gasket. Any other signs of overpressure?

Bob, thanks for the reply....Motor runs just fine no intrusion of oil into the coolant, plugs are dry no smoke of any kind. I doubt it was overpressure thinking more like metal fatigue or stress crack. Spoke to FF and although they said this is not a common failure they have heard of it in the past. Just to be sure, when I reinstall, I'm going to remount it using rubber pads at the attachment points.
Best
Bill

[GFX2043mtu]

Hard to say with out seeing it. It could have been a bad tube weld or improper tube annealing as they are made from flat sheets that are laser welded and rolled to shape. Bummer is it can't be fixed easily. Also over pressure can't happen unless your system is plugged or you are running the wrong cap. As it's meant to vent excess pressure and can do it very quickly if needed.

[WBILB]

UPDATE. Found a shop that specializes in aluminum radiator repair. They popped off the two side tanks and "capped" the offending tube on both ends and re welded the tanks back in place. They said that the tube split/cracked at a seam, probably metal (or weld) fatigue. They were very confident that the fix would be "permanent" and I watched them pressure test it in their water tank to 35PSI with no bubbles. Thanks to Bob and GFX for your comments, still would like to know if anyone else has had this occur. Will install this AM and see what happens. BTW, assuming a successful effort, the repair was $85... sure beats $299 + shipping.

[Renegadezx]

UPDATE. Found a shop that specializes in aluminum radiator repair. They popped off the two side tanks and "capped" the offending tube on both ends and re welded the tanks back in place. They said that the tube split/cracked at a seam, probably metal (or weld) fatigue. They were very confident that the fix would be "permanent" and I watched them pressure test it in their water tank to 35PSI with no bubbles. Thanks to Bob and GFX for your comments, still would like to know if anyone else has had this occur. Will install this AM and see what happens. BTW, assuming a successful effort, the repair was $85... sure beats $299 + shipping.

My rad failed at 5,000 miles and I replaced it with another FFR. However the new radiator came with different expansion joints on the side which protected the core from stress. I have photos of both radiators and the change if you are interested.