Safe high water temp

[dredgeguy]

Last weekend I got stuck on the highway in gridlock traffic. Three hours of 1st gear creeping along with outside temps of 97. My water temp stayed around 225 but at one point went up to a max of 235. When traffic opened up and I got rolling, my temps went back down to 195. I have a new DeWitts radiator put in 1 or 2 years ago.
My question is this, if the temps kept going up, at what point do you pull over and stop the car and give it a chance to cool down? At what temp are you starting to risk engine damage?
Thanks

[Dynomite]

That is a difficult question but this will give you an idea of the absolute high coolant temperature....

You get over 260 for any length of time and depending on the age/miles of the engine bad things begin to happen. The location of the water temp pickup can result in a misleading temp on the guage if there is low water in the motor. It is one of the first locations to see steam vic water which results lower temp reading. You need to watch oil temperature reading too.
Tyler

The key is to keep rpms up over 2,000 rpm to keep coolant flow over 45 gpm more or less. Idling in traffic at lower RPMs just is not enough coolant flow no matter what radiator you have and no matter when your fans come on.....get a Haibeck chip and turn fans on at 205 deg F and off 200 deg F.

Thermostats, Fans, Radiators and Coolant Filling (https://www.corvetteforum.com/forums/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-6.html#post1584987828)

[nelson007]

Charlie,
I put 16” Hayden electric fans on all my big blocks. Keeps tems around 205 max.
Nelson

[Ccmano]

On a fully stock engine the second fan doesn’t even come on till 234 degrees. Since you topped a 235 sounds like this might have been the case. On a 97 degree day stuck in traffic with the AC on the stock cooling system on these cars is simply tapped out. If it holds under 240 I let it go, anything over 240 I turn the AC off. A Haibeck chip that turns both fans on at 205 will buy you some more time. Ultimately as the ambient temps exceed 100 degrees you will be forced to manually cycle the AC on and off to prevent overheating.

Read Dynomites excellent write up on the subject in the link he attached in his post above. He provides a great synopsis. Even with a radiator upgrade water pump circulation at idle is simply insufficient.
H
:cheers:

[dredgeguy]

Great info and thanks. Looks like I needed to get my RPM's up and I would have been ok.

[rkreigh]

hey Charlie, I just pulled the front cooling stack apart on the old lsv and was surprised to see about 40% clogged up dewitts


I also found a set of stronger fans I'm going to try


with the thick rad, the factory fans aren't strong enough to keep in cool creeping in traffic with the ac on


gets worse as the displacement and compression go up as on the LSV


I'll let you know. for sure DON'T run the car above 245 or you will be doing just what I am. Replacing head gaskets.


As marc explained the car overheats and "crushes" the HG as the alum expands and after a few of these cycles it won't recover and leaks


technically the car isn't "overheated" at that temp but your HG will thank you for running the car below 230


Ask me how I know

[Paul Workman]

After my secondary fan died in 90* stop and go traffic, it got up to 245*+ a couple times before I pulled over to let it cool. Then the temps surged to ? before cooling off. No problems, but later Marc said I got lucky.

I've installed a screen stretched between the air dam and the radiator to keep the grass etc away. Turns out to be a very good mod indeed!