mcfly5

I just replaced the stock 195F thermostat on my '79 L-82 to a 160F in an effort to get it to run a little cooler (i only drive in the summer of course). any issues that could arise from this or is there any better suggestion (short of an aftermarket radiator)?
thanks much
mcfly

jn79vette

i recently did the same thing.with my dual electric fans my car never runs over 160-170.

Ganey

You want a min. of 180. See chart at bottom of http://performanceunlimited.com/illu...ermostats.html

Won't run 160 w/ 160 & stock cooling system except maybe close in very cold weather.
EFE could be on all the time.

Rod out rad.! Seals in place. Then could use 180 stat.


[Modified by Ganey, 10:37 AM 3/29/2003]

page62

Ganey's right. Pull your rad and have it boiled at a shop. Recore if necessary.
Also flush your engine to get any crud out of it. Make sure all the foam seals around rad are in place. A replacment kit containing these bits sis recommended.

And if the stock air intake is missing, that can cause cooling problems too. It normally fits over the top of the rad. If it's gone, air blows over the top of the radiator instead of through it.

Finally, install an overdrive transmission (no kidding). With reduced RPMs on the freeway, my car cooled off 20-30 degrees!

s79vette

I've run a 160 for the last seven seasons and my temperature runs at about 190.
I've never had a problem with running hot since install. My radiator is clean and
I get a good flow of coolant thru system. I ain't an engine expert and maybe
I'm harming my motor but it runs good doesn't overheat in the summer and
my a/c blows cold air. I'd like to install a newer heater fan some day but it looks
to be quite a job. There were some posts on installing a late model fan on C3s
a while back to increase air flow, I know I printed it out to save for future
project but it hasn't been a priority. Steve

Stoge

I have a 180° thermostat in my '79. It does not get warm enough in winter, but I have no cooling problems in the heat of summer. My A/C is broken (has a freon leak somewhere), so I don't run the A/C. My factory electric fan runs every so often.

My problem lies in my radiator. I took it out last spring to have a nasty leak repaired. It was the first time the radiator had been removed from the car. Let me tell you, I beat the crap out of the radiator during the process. I just don't see how anyone can get the radiator out of the car without tearing it up.

I'm going to have it recored at the radiator shop who fixed the leak. The guy said it would run around $200 to have it recored, but it would look factory and retain the original tanks and the number tag. Sounds like a good deal to me...

On the other hand, if I get a crate motor at some point, the factory radiator will probably have to be replaced with an aluminum radiator and electric fan set-up from Tom DeWitt.

By the way, I'm thinking ZZ4 at some point...


[Modified by Simon Alexander, 10:07 PM 3/29/2003]

WhyFly

Good advice given in the previous posts. There's a number of things to try before going to an aftermarket rad. You don't want to run your car at temps much below 175 to 185 or so as the car will run better and be more fuel efficient as well. You need some engine temp for proper atomization of your fuel. As mentioned above, have your rad redone, try a 180 degree thermo. make sure your seals are good and belts are properly adjusted and if that fails, try a high flow water pump. Bottom line though is if your running hot, it usually means there is something else not right. Check your timing and water/antifreeze mix. Good Luck.... Let us know what you do and how it works out.. :thumbs:

isosceles

and if you haven't already done it, either have your system pressure checked or replace the radiator cap for good measure. The guys at Van Steel pressure checked mine and found the cap bad. They replaced the cap the now it runs 20 degrees cooler. I still get up to 220 when cruising at 70 (yes my foam seals are intact) , but I was hitting 240+ before. I sit at 200 or below around town in the heat of the summer. I think I'm going to try a hi-flow water pump, mine is starting to rattle. :smash:


[Modified by isosceles, 5:20 AM 3/30/2003]

timbo79

160, but I also have a ccoling fan (dual) that helps as well as aluminum Be Cool radiator

Ganey

A rad. shop can rod the rad. out for as little as $50 which should do it if all else like seals are good.

Paul L

I tried a number of products and temperatures and for me it all comes back to 195 and this brand. My car runs from 195 to 210 depending on ambient temperature. That range is normal for a 1979.

AlwaysWave

Keep in mind that the t-stat controls the minimum engine operating temp, not the max. As a few of the above posts pointed out, their running temp is higher than the t-stat rating. If your system wants to operate at 200 degrees it will do so regardless of a 160, a 180 or a 195. The t-stats will be wide open all the time at 200 degrees.

mrvette

I find the diameter of t-stat openings used to vary quite a lot.....you see once the thing opens, that's it, job over....it opens at say 180f any way it ever closes is if the water goes below 180 again....winter time every radiator is super efficient....now comes summer...thing opens...but with the smaller flows available, like the 195f stats...you get the same flow as a 195 stat, and the system runs at 195 or higher in summer....same thing in other words....
if you go to the shelf there and examine closely all the stats you willl eventually find one usually in the 160f pile...with a slightly larger opening...
the differance is about 1/8 inch or so....but it makes all the differance in the final operating temp...high end....
I think they quit with the larger openings because of an EPA issue somewhere....

GENE

Ganey

Yes, the no. is the opening temp., not fully open until about 25 degrees later.

Paul L

Quite so. Then the cooling efficiency is a function of the condition of the rad, rad support seals, etc. Let's also not forget that a system with a 50:50 mix of coolant/water under 15psi of pressure is designed to operate above 212F, the boiling point of water. BTW, the red area on the 1979 temp gauge starts at 260! The auxiliary electrical cooling fan (when so equipped) was switched at 238F. These temps are much too high for me but they do indicate the robustness of a well-functiong system.

AlwaysWave

I respectfully disagree. I made some boiling water pot tests last year on 180 and 195 t-stats. They started to open roughly 10 degrees early and were fully open within 5 degrees of rating.

The reason for my tests were multiple, but basicly I wanted to eliminate the temp spike I was getting on warmup. I now run a 180 with one 1/8 hole drilled in it.