I have a Griffin aluminum radiator in my 56 LS1 car. It started leaking at the bottom. Took to a radiator shop, and they soldered it at the bottom. No leaks now.

One caveat issue: Having installed, but not test driven, while on vacation, my son-in-law called to ask if he could drive it. I told him yes.

Got a call later and he said the radiator was leaking and it got hot...up to 220, so he parked it back in teh garage. Said it was sizzling/gurgling and water leaking.

when I got home and checked some things out, I found a couple things: First, I had not yet put in antifreeze, as I wanted to test drive first. That explains the boiling when at 220. Anoother thin I found was I had hooked the front pusher fan up with polarity reversed, so it was pulling.

So I put in antifreeze, corrected fan, and test drove. Seemed fine.

Now, I took it on a 500 mile round trip this weekend. It cool for about 40 miles, and slowly heated up, to about 205. But it held steady. Interestingly, it ran cooler when driving slower.

Coming home, weather had heated up some, and it ran just under 220 for quite a ways home.

This engine always ran way cool, in fact I was stumpted as to why so cool. Even though I have a 195 thermostat, it would run well below that when on the freeway, and of course run to 208 to turn on the fan in stop and go traffic, and when fan came on, it would cool down.

Now, finally, for the question: Is it possible, (or probable), that solder repairing a leak in a Griffin aluminum radiator would end up with faulty cooling capacity?

I hate to spend $600 if it isn't the radiator. Thinking of replacing the thermostat, but I'm thinking if it was the tstat, it would run hot all the time.

I'm thinking that 220 shouldn't harm this engine, even prolonged. I'm not seeing steam come from back end when I get on it. So I don't think its a problem with engine.

I'm stumped, but thinking I need to bite the bullet and get a new radiator.

Whatcha think?

 

Try driving it for a little while and then putting pressure on your radiator cap and seeing if the cap wants to pop off, I had a similar problem and it turned out my whole system wasn't maintaining pressure cause my cap was leaking. Just a small thing to check

 

INteresting...I'll give that a try.

I have a cap that has an aluminum cover over it. I don't even know what pressure it is. What pressure should I get? I'll get a new cap and put it on.

 

220F won't hurt an LS1. factory settings for electric fans on the 4th gen f-body is 226F for low speed and 234F for high speed.

if they dripped a big blob of solder into the radiator and it's causing a restriction then it would hurt cooling capacity but you would have to be a real schmoe to do screw up that bad i think. I would put a new thermostat in, that's cheap and easy.
The norm is a 15 psi radiator cap, 50/50 coolant/water mix won't boil until 265F.
A lower pressure cap will result in coolant being able to boil at a lower temperature and when it boils it can't transfer heat.

http://avenger-valkyrie.org/techinfo/antifreeze.htm

 

220 is a fine operating temp. 210* is actually optimal operating temperature.

 

Thanks for the input.

I just picked up a radiator cap. They didn't have a 15# one. I got a 16# one. I presume that will work OK.

I'm going to take it out for a while and see how it goes. If it still gets hot, I'll try a thermostat next.

I was pretty sure 220 wasn't a problem. While it isn't a problem, it is running so much hotter than before the radiator leak, I'm concerned, and don't want to chance a trip.

I had been a bit concerned that having let the engine get the water boiling (when I didn't have antifreeze in it while my son-in-law drove it), that maybe that caused an issue somehow.

I'll post back the results of this test drive.

 

In 100 degree heat with the AC I've seen mid 230s and even almost 240 and the engine was perfect. As stated stock fan setting dont even begin to apply until the mid 220s.

 

I've always been under the impression the stock LS1 radiator cap was 18psi..... Mine is.

 

^^yep should be, and I think that is pretty standard in the automotive world.

 

yup....
and its standard in the industry to be 15ish psi in the cooling system itself




its not an issue to put on a head gasket, torque it lightly to do PTV.
the gasket will be fine, and its not like you are putting any load onto it or sealing to a hot cylinder...