Aluminum radiator repair this winter.

[289fia_cobra]

Well, with winter coming in hard, I may be putting the car into winter maintenance mode very soon.

One of the first things on my list is to get my radiator fixed once and for all. It is a Ron David radiator and it's been fixed once before but I think they only fixed the one tube they knew was leaking. I developed another one shortly afterwards but just didn't want to ship it back to Arizona again so I rather just have it done locally.

I'm thinking of using "Advanced Welding" in Mountain View since they've repaired a hole in my old cylinder heads a few years back but wanted to see if anyone else has recommendations for other shops. Have to really know how to weld aluminum, especially the thin tubes, and do pressure tests ( 16lbs or greater pressure; don't know what they use to be honest). And of course, a guarantee of their work for at least 30 days.

In the worst case, if they simply cannot fix the offending tube(s), then to simply seal it up on both ends. It's got more cooling than I really need anyway so I won't miss it.

TIA

[Rick Parker]

If the header plate uses epoxy to seal the tubes (many do) you would be well advised to eliminate the offending tube rather than attempt to weld it. Also, if you haven't already, consider welding a small pad on one of the tanks and attach a ground wire to avoid electrolosis & corrosion after re-installation.
BTW, I am in the same situation regarding overcooling. Unless I am in the throttle the radiator has more capacity than necessary. Sometimes I block off part of it.

[289fia_cobra]

As for the electrolysis, I do have a zinc anode installed.

You are not suppose to ground the radiator. I've read the instructions thoroughly from Ron Davis and part of my problem was the fact that it was touching a ground source - the frame! When I finally finished installing it after repairs, I took a continuity tester to it and there was NO contact to ground.

It's just that the second leak was likely either too thin to stay repaired as you were alluding to, or my original electrolysis problem affected an adjacent tube.

After thinking about this some more, I'm inclined to just remove the entire tube and seal it like you suggested. There's no point in putting heat to it again and possibly fatiguing the tank any more.

Thanks for your reply.

[4pipes]

I just replaced mine. I was told that trying to repair aluminum radiators is futile.
In my case the radiator was $500 from Kirkham.

[xb-60]

Originally Posted by 289fia_cobra

As for the electrolysis, I do have a zinc anode installed.

Depending on what alloy of aluminium the radiator is made from, the radiator could actually be the sacrificial anode instead of the zinc. Alum alloy and zinc are very close in potential difference. Can you connect a meter to the zinc and the aluminium alloy radiator, with the cooling system up to temp, engine running, and check which way the current is flowing? Magnesium for an anode would be better...
Cheers,
Glen

[scootter]

Herman,

We live in California, there isn't a winter!! I just went for a good ride yesterday and the weather was great. As long as it's above 45 degs and not raining, it's drivin weather!! Since it was raining today, my son and I had to go dirt bike riding!!

Scott

[Tom Howland]

I have a Ron Davis radiator (epoxied) that developed leaks at all 4 corners. I cleaned them very, very well(dental picks and acetone) and put epoxy on them and pulled a vacuum on the radiator to suck in the epoxy. So far it's holding up.

[Paul F]

Note that Griffin radiator says to measure voltage from the radiator fluid to ground. To me that means it doesn't matter if your radiator is grounded or not. It may still be the victim of electrolysis.

FAQ Electrolysis : Griffinrad.com

[289fia_cobra]

I understand that part. When I was testing, I only showed some .04volt but that was AFTER the first repair and I had isolated the radiator. I still believe part of the problem wasn't necessarily electrolysis but more my fault for hard mounting the radiator up top and a small amount of flex imparted onto the radiator started the leak.

I guess I could use the Permatex Radiator repair epoxy and do this myself.

[PANAVIA]

How did these cracks form >? vibration / twisting >?

[289fia_cobra]

Steve:

Full history:

The FIRST RD radiator, I hard mounted the radiator; the upper right corner tube (very top) developed a leak within a couple of months. I took it to a shop that "said" they could repair it; they could not fix it and made it worse.

I purchased a 2nd radiator (the current one) and tried to isolate it from the chassis a bit. Well after 6 months or so, I began to see a drop of antifreeze.... a few months later, more dripping. The leak was in the same location - upper right! But the radiator had been touching the aluminum for the forward nose cowl (to keep air from bleeding off the sides) and this grounded the radiator. I sent this radiator back to RD and they said they saw signs of electrolysis but they would go ahead and repair it. Well that lasted only a few months and again, I was getting the leaks., despite totally isolating the radiator from any metal that could ground it and that was also when the Zinc Anode went in.
My guess is, they repaired it, but maybe I had a marginal tube next to it that was on the cusp of leaking so they never saw it.

So for the last two years, I've simply let it leak as it only happens under heavy acceleration (thus the spotty engine bay) and when things cool down. But this winter I figured I'd get it taken care of. I plan on simply closing the offending holes rather than repair the tube. Not sure but I would venture a good epoxy (I have some Permatex Radiator repair epoxy) should do it. I don't need that much cooling as most of my trips, my oil barely gets to 180 much less 150F. If I get rid of the top row completely, I would bet it would make no difference at all. I will be doing a pressure leak test to see if I've developed any other holes since it'll be out of the car.

[PANAVIA]

Sounds like a good plan - I would consider JB weld as well, as long as you can get everything "Dry" and let it cure for a couple of days in a warm room (or under a UV lamp)

We have had good luck with RD, and recommend them highly. Dennis and Bill are very helpful. -

[289fia_cobra]

Thanks for the tip. I figured it would be best to keep them "warm" while it cures.

[PANAVIA]

Correct - warm is happy.

[Rick Parker]

I recently saw an advertisment for C/R Radiators that had a full blown implied endorsement linked Shelby for the current Mustang upgrades and made it sound like for Cobras as well. Has he changed from Fluidine??