Thought I would bring you all up to date
I have been fighting an overheating problem for quite some time..
Tried all the recommended fixes..
Flushed the system, new thermostat, new fan clutch, sealed the shrouding, water wetter, more antifreeze, less antifreeze, aux electric fans, the list goes on and on...
Engine would run 180 when on the road and moving.. In traffic 190 to 200 was the norm.. Long lights would quickly exceed 200..
Not too bad right... Most of us are in this ball park..

Add the AC, and all bets were off.. 200 became the lowest I could expect at 55+ on the highway.. At slower street speeds 210 became the norm
I feared long lights as the temps would climb to 220+ and I would be forced to shut down the AC until I could get moving again..
All this on a fairly mild 80 degree day..

Polls on this forum indicated that most of us were running at about the same temps.. I was accepting that this was normal..

While at local car shows, I ran into a several original owners of these cars and all of them said that they never ran that hot, even with AC..

I tried to get some of our original owner members to speak on the subject but no one responded..

I quickly tired of having to watch my temp gauge..
I decided to bite the bullet and get a new radiator..
I looked at several, since my car is a fairly original low mileage car I found that there was only one real choice Dewitts
I ordered it and it was at my door in short order..
I have to say that it is a perfect match with the original..
Can't tell the difference with a side by side comparison..

The real question though is "What are the temps now"...

I was very surprised to find my temps dropped to 170 around town..
Even with the AC on, the temps never go higher than 180 even at long lights..
I was stuck in traffic yesterday due to road work and the engine temp stayed stable at 180 with the AC on..

Man, I don’t have to watch that gauge any more!!
What piece of mind… Well worth the price..
I can now really enjoy driving

Guess even with low mileage, the crud still builds up in the radiator after all these years.

Tony

 

COOL!

I had the same results. It's the design of the DeWitt which is totally different than the original.

Good for you.

 

This goes back to something from prior threads. I think JohnZ said it. MORE RADIATOR is usuallythe answer. Assuming of coursr that the old one is indeed just old and tired like a lot of these vintage parts usually are.

Good news Glad to hear you solved the problem. I used a Griffen and had the same results.

 

Radiator deposit buildup and corrosion is primarily a function of time. The gremlins are at work even if the car isn't driven, and that's why antifreeze should be changed every two years regardless of mileage. The glycol doesn't wear out, but the anticorrosion inhibitors are depleted with time. My experience is that the Harrison type aluminum radiators will corrode and begin to seep before they clog up, and brass radiators are just of opposite - they clog up before they begin to leak.

In any event, with good maintenance you should get another thirty years service. I use GM Dexcool (Havoline Extended Life) in all my cars now. It provides better corrosion protection for aluminum, and since it contains no inorganic salts, there's nothing in it to precipitate out and clog up the tubes.

Duke

 

This was somewhat a surprise to me as this car has very low mileage..
I was told that it is very much time and not miles that crud up the radiator..

Still a new radiator isn't cheap..
I tried everyting to avoid the expense.
Looking at my old radiator, it looked fine.. Actually it looked almost new..
Could this really have been the problem???

It was only after talking to several original owners, telling me that when new the cars never ran hot that I decided to go for it..

I can now add my own experence.. to the mix..

A Corvette doesn't have to run HOT


It is 80+ today and even with the AC on the temps never even get to 180

I am running a water antifreeze mix of about 60/40

Should I be using distilled water?? Does it really matter..
I plan on changing this stuff often to keep it running cool

Now it's way :cool:

Thanks to all who responded to this and past threads on this subject..

Good luck to those still fighting this problem
Hope this has been some help.

Tony

 

I'll assume you had the radiator flow tested. A good radiator shop can tell when the tubes are plugged. Unlike a conventional side tank brass radiator, the furnace brazed 316 aluminum radiator cannot be disassembled in the field and rodded out.

If you're certain the old 316 is toast think about dissecting it to do a failure analysis.

I always use distilled water mixed with antifreeze. You can get away with clean potable water, but for the cost, distilled is good insurance and keeps the trace amounts of inorganic salts present in all drinking water from getting into the system.

Duke

 

Thanks SWC Duke
That's what I was thinking...
As you know the water here is very hard..
Lots of mineral content.
Although it lasted 35 years I would like to help it in any way I can..

As far as the flow test,
A Local shop at first thought the radiator was OK..
He said it looked great.. :rolleyes:

I guess the only way to really know is to somehow measure the actual BTU dissipation rate..

Since he didn't really see anything wrong with it..
that is one of the things that made me wait as long as I did to replace it.

Figured it must be something else..

I even started questioning the AC, wondering if the FR-12 replacement refrigerent was causing too high a head pressure and excessive load on the radiator..
This was due to the fact that it seemed to overheat only with the AC on..

I tell you the radiator looks good no buildup in the top or bottom hose connectors can be seen.. Exterior looks like new..

I assume that because of the cross flow design, the bottom tubes must get gunked up first.. Then through the years the gunk fills from the bottom closing more and more of the radiator..
All it needs to do is plug the left side and the radiator is toast.

I back flushed it many times trying to clear it up.. Water was clean..

Finally gave up..

I love to drive my car..
I wouldn't have bought it if I couldn't

I would love to open it up and see where the problem was,
but I will keep it and let the next owner re-install the original when he loads it up on his trailer :lol:

Tony

 

Glad to here everything is working good! td

 

Kahuner: Did you have the same result with a brass BB radiator from Dewitt, or was the replacement also an aluminum radiator? Also - if the car with the Dewitt was a BB, did it have A-C? My recored brass is holding down the temps for about 7 years, and the previous recore only lasted 6, so if a replacement for a BB car with A-C works, I would like to know. I ran with a BB 67 to Sun Valley that had a new overheating aluminum unit on a noA-C 400hp BB. I was not impressed, since my (then) 5 year old brass recore had no problems.

 

...congratulations...yeah, i've found out the hard way, just buy another radiator and do the common sense things and it will work out...fwiw, i always drain the block before swaping in a new radiator - what a bunch of crap in those old blocks :yesnod:

...for the roadster, i bought a blem "be cool" at fall carlisle - less than half price and you can't see the blem with the shroud on :cheers:

 

Magicmachines, obviously you've have a bad experience with aluminum radiators. I don't know who's brand it was but I believe that the Griffin HP series would solve any BB problem, even AC cars. The model I offfer for your car uses 1 1/4" wide tubes (Be-cool uses 1"). If you're interested email me and we'll work out a special $. td

 

MagicMachines;

I didn't catch your question on this thread until today.

I installed DeWitt's alum direct replacement shortly after buying my car last Feb. Didn't even run the car with the brass unit that was in the car when I bought it, after reading all of the stories about overheating on this site. I swapped out the rad because the car had almost no miles put on it in 10 years.

As far as running temps, it never gets above thermostat temp which is 180 deg. and I do not have the sealing strips installed. I'd have to say my experience with this rad has been all positive.

My car does not have AC.

Don't know if I answered all of your questions. If not, give me a shout.