Thoughts on why I am busting radiators?

[98Fauxbra]

Hey Guys,

I am having a problem with my wife's 66 mustang. It has a 289 in it that is mostly stock. It does have air on it (old school style that has been converted to 134). I replaced the radiator 4 years ago when she first got the car with a 3 row from Advance auto parts. Never had a problem with it till Feb of this year. On my way home from work, I started smelling coolant and by the time that I got home it had split the seam right under the opening to fill the radiator. I thought that it was a bad weld on the radiator. The radiator had a lifetime warranty so I took it back and swapped for another one. Put it in and all was well (swapped in a 3 and 1/2 inch fiberglass fan shroud at the same time). Well, coming back from the 45th anniversary show it BUSTED the radiator seam right in the same spot as the first one. Really nasty this time as it split like 4 inches!!! The car has been sitting for 6 weeks because life got in the way. I am finally free enough to get some time under the hood. Could it have been two bad radiators in a row from Advance? 4 years apart? I am trying to figure out if I could have another problem. The lower radiator hose has a spring in it and is in good shape. I have a 180 thermostat in it (I am going to pull it and swap for a 190 though while it is apart). I have a stock style water pump from Advance that seems to be just fine. My only concern is that I was running a 16 pound cap on the radiator. Could that cause the problem? I can't imagine that 3 pounds would make that much difference. I am wondering if the cap could be bad (it is less than a year old) and it is holding WAY too much pressure. Any other thoughts on this equation? Anything that I might be missing? Money is not growing on trees right now so the free replacement radiator is surely enticing! Pulling the radiator out of her car with power steering, air conditioning, and an automatic is a chore at the least, and I have done it twice this year already, so I am also weighing my other options too. I would appreciate any thoughts and suggestions. Thanks for your help! I can't wait to get it back on the road.

 

[jcode68]

Do you have rubber isolation pads on the bottom of the radiator where it sits on the frame? Check the upper mounts too. If not, you are subjecting the radiator to taking the impact of every bump in the road with metal on metal, which is pretty harsh. It could be manifesting with cracks in the same location if this is the weakest part of the radiator. It could also be just poorly made radiator and yes it is possible to have the same failure on the same part 4 years later. The last radiator you put in could be 4 year old stock.

 

[sparky]

Had the same problem on my 66. Ended up taking the new radiator to a radiator shop and had them
solder all the seams & connections. So far knock on wood, nor more leaks. And yes, the radiators are being made overseas.

 

[66 Restomod]

I had a 13# cap on mine and bought a replacement at a mail order place. A 14# cap showed up and I checked a Shelby book I had on hand. It appears 14# is usable, at least for K-codes anyway. I figured with my modified car it should be Ok. So I'd switch to a 13# or 14# to be sure. I think it's about $20. At the very least your next free radiator should really last more than 4 years with a 13-14# cap.

 

[2+2GT]

Do you have rubber isolation pads on the bottom of the radiator where it sits on the frame? Check the upper mounts too. If not, you are subjecting the radiator to taking the impact of every bump in the road with metal on metal, which is pretty harsh.

No, the 64-66 radiator was attached by two bolts each side to the radiator support. The top & bottom saddle mount didn't appear until 67.

 

[HookandLadder]

That 16 cap is probably bad and too high. You need a 14. You wouldn't think 2 lbs would matter much but it does.