ZeroToSixty

I have a 160 degree thermostat installed in my C5 (along with a Chuck Cow tune) and my coolant readout ranges from 170 to 194 degrees.........is this normal ?

Is it possible that there is some air in the system that causes this jump to 34 degrees above the thermostat setting ? Or is there another reason the range is so great ?

Evil-Twin

You will typically see higher temps in the 210/ 220 range in stop and go traffic under 35 mph. a thermostat has no control over the upper temp, only over the lower temp range.. a 160 stat means the coolant will never go below 160 F. once the stat is open at 160 it has no ability to cool anything. electric fans are designed to cycle on and off to help with their shelf life. If the fans were to run constantly, they would not last 6 years.
heat is transferred from the cooling system via the radiator and the draw of air across the cooling surface via the fan's speeds or vehicle speed above 35 mph..
also the variation in temps is very normal
the over heat temp of A c5 IS IN THE 260 RANGE, anything below that is within spec. the usual culprit ojn the C5 cooling system is debris in the ac condenser and radiator which prevent a complete flow of air through these two components.

3boystoys

160 degree thermostat only opens at 160, the rest of the system hasn't changed. If the retune changed the fan settings, that would have more to do with the temps your seeing. 160 degree t-stat is a waste of $$., all it does is open sooner.

skydiven4fun

Just curious why you state that they are a waste, I only go by recommendations from either here on the forums or the shop I use for my work (Englandgreen) I understand how it works, but just curious on why you think it's not worth the effort ?
Of course some of us live in the South where it's extremely hot 3/4 of the year.

tacman

Really?

As I said in the Tech Forum, this should be the subject of a Sticky. It seems to show up every week or so.

3boystoys

Because it really changes almost nothing. Reprogramming the fans does more to lower coolant temps. All the number on the T-stat does is tell you when it opens. All this means is that it takes longer for the engine to get to the proper temp. Once the t-stat is open it's just as open as a 190, the steady state temp of the engine won't really change, just how long it takes to get there. So, it's a waste and if you drive your car in colder places, it takes longer to get heat in the cabin.

I've driven mine in 100+ degree heat many times and with a stock T-stat got in the mid 220's a couple of times till the fan(s) kick in. Never an issue. My Hemi Challenger runs almost the same temps as the Vette, modern engines are DESIGNED to be fine at these temps.

Evil-Twin above had a long dissertation on the subject and he worked on the C5 at the factory, try searching for it.

Evil-Twin

I did Not work on the C5 at the factory, I worked on the C5 project at the GM engineering design Center from 1995 through launch in 97 and then three years of engineering field support, debugging field problems until I retired.

skydiven4fun

Thanks for the response, it seems that most shops sale their cam kits with the lower temp thermostat, I never had any issues prior to my build or since for that matter, but it seems to be a topic of discussion on here often.

Evil-Twin

A colder running engine can get you more power.. More power is the job of a tuner. adding some advance is like giving you free HP.. what they don't tell you is running a cold engine can reduce the life expectancy of a typical stock LSX engine by 50 %. You really do not want to run an LSX engine at 160 F. for long periods of time in cold weather where the coolant can see ambient 20F. remember a stat controls how cold your engine can run, not how hot, so if you have a 160 stat and its cold outside your oil will never reach the sweet spot, and the oil will breake down from shear. Hot is a friend to the life of the engine. cold is its enemy. You choose horse power or 400 K on the motor.
Bill aka ET
I have some knowledge in this area.

skydiven4fun

Thanks for explaining that Bill, it makes perfect sense, I think most of us have always thought that heat is the killer, but its really a balance between hot and cold and being able to reach and maintain the perfect temp (or within the specified range) that we need.

James2002z06

That's what I like about him , he doesn't have a fu..ing clue ...except to run people down

Camjamsdad

My 160 stat runs 169 to 174 which is about 10 degrees below what I want to run it at. I had a 180 and it ran 189 to 192. Fans were set for the 180 stat. I swapped to the 160 without changing fan settings yet I have lower temps. The thermostat holds water in the block long enough to allow heat transfer. Run without a stat and you'll over heat, not run cooler. The rated temp is the start to open, not full open temp.

olbear1962

I have the std thermostat and it runs in the 196 to 212 range here in Wisconsin, in Dallas she used to run up to about 216-220 max in the summertime when it was 105+-
My tuner didn't want it too run too cool, as per Evil-Twin comments.
The tuner did change the fan cut in time to compensate for the higher ambient s in Dallas.

ZeroToSixty

All good info,...........thanks for the responses.