Radiator leak

[JohnPR]

I’ve got a gen 1 coupe, with the aluminum Afco rad. It developed a really mild leak somewhere on the passenger side a couple of years after I got it on the road. Over time, that leak got a bit worse, so I had the rad inspected at a local shop, but all they could do was try to epoxy it. That worked for a while, but now it is leaking again, a bit worse.

I seem to remember reading somewhere that this is a pretty common problem with these Afco rads, so I am reluctant to just replace it with another one. Does anybody know of another rad type that would fit into the same spot, even if it’s not aluminum?

[mike223]

https://www.summitracing.com/search/part-type/radiators/brand/summit-racing

I've had good luck with one of these in Mk4 for several years.

Not sure what size you need for the coupe.

I did take mine to an aluminum radiator shop and get it modified a couple of times (pretty cheap to modify).


Most important - make sure you have a good ground from the engine to the battery - otherwise you set up galvanic corrosion when amperage from the starter makes it's way through the antifreeze + radiator to the frame / battery - this will make pinholes quick.

A sacrificial anode is a good idea in aluminum radiators too: https://www.summitracing.com/search/department/cooling-heating?N=4294950709&SortBy=BestKeywordMatch&SortOrder=Ascending&keyword=anode

[JohnPR]

Thanks Mike. I’ll need to measure mine and see if there is one of those that is a good fit. I’ve heard the Coupe rad is from some production vehicle, but upside-down... but not sure what that vehicle is.

Since the rad is on a slant and I’ve already got a filler cap / overflow fitting in-line in the upper hose, I’ll see if I can find one of those rads without a cap opening. Now that I think about it, that cap would just get in the way of the tie-down bracket anyway.

Thanks for the tip on the galvanic corrosion- I didn’t know about that. I think my engine-to-chassis ground is pretty good, but I’ll check it again, and can’t hurt to install one of those anodes anyway.

Thanks.

[mike223]

I’ll see if I can find one of those rads without a cap opening.



The two mods I had the radiator shop do on mine were eliminate the cap opening + add a bung for the anode (put it in a good place to drain radiator).

I think I paid them $50 - I think the radiator was $159, but I think I caught it on sale.


P.S. It's also handy to have a bung in the top of the radiator to get air out - that's what I did in place of the radiator cap fitting - but that's not a good place for the anode (if there's any air, and there will be).