I recently had a 160 degree thermostate installed along with ported ls1 heads/cam. The coolant temperature is NEVER over 183 while cruising, and alot of the times it's down around 174 degrees. I fear this may be too low a temperature to be running! Sure would appreciate any insight into my dilemma!!!

 

I did my own study of what other manufacturers were doing with the temps on their cars. Mercedes likes 185 degrees and they run some of the highest compression engines on the planet. I have a 170 degree stat and my car runs in the low to mid 180's depending on the outside temperature. At 75 degrees outside, I run 185 on the freeway. In town at 200 degrees, I turn on the air conditioning, which tunes on the engine fan cooling me down to 190/192. Ideal is 180 to 195 in my opinion. I had a 160 stat and ran in the high 160's to mid 170's which I thought was a bit to cool. What you have to worry about is running hot at 220 and then hitting the freeway for a quick cool down to 168 creating a lot of expansion and contraction. Over time, that might not be good. If I had to error, I would error on the hot side. Our best power comes in the low 190's. Our engines will last longer if they run a bit cooler say in the mid 180's.

Dan

 

What is your oil temp? I bet it's not getting hot enough.

 

Thanks for the information Dan, and Droptop. I too think the coolant temp is a little low for my application. I don't race much. But I've got a Lingenfelter installation, and I would think they would know what's best for my car. My oil temperature does seem to get up to "normal" operating temperature, about 190 or so.

One of the reasons I became concerned is because 02 sensor codes are being displayed which LPE tells me is because I have high-flow cats, which they WON'T install, and I did before I took my car there. They say the codes are being displayed because the sensors sense that my exhaust is too cool. But, I had the Dynatech headers and high flow cats on the car when I drove it 750 miles to Decatur with NO codes!!!

 

http://forums.corvetteforum.com/show....php?t=1041940

 

I read the thread in the link you posted Evil-Twin. I believe the point you might be making is that you too think my engine might be running too cool, also. I truly don't think it should run hours at hi-way speed at or even below 180 degrees. I would think that LPE would know what's best though??? I do know this, that as far as the high-flow cats being too cool, as per engineer at LPE, I drove the car with those same cats to Decatur from home, about 750 miles, NO ISSUES PERIOD!!!

 

I have intimate knowledge of the oil life monitoring system. The system was designed around this aluminum LS1/Ls6 engine design for clearances, oil suspension properties, and lubricity. Modifying your engine will change some of these aspects.. I do know that a cold running LS1/LS6 will carbon up prematurely and is the reason why the GM decarbonization process is used in these situation.. the stock LS1/6 has a sweet spot in its factory design.. The engine runs at it's best in the stock configuration at 190/200 coolant, and 200/210 oil temp. This sweet spot refers only to engine internal integrity. Carbon buildup can cause increased compression and knock sensors to retard the spark for engine protection at the expense of poor engine performance. Also High Heat in the summer, and low octane gas (91 ) can contribute to this condition.. KR is telling you something is wrong.

 

Personally, I think it is too cool as well. I lowered the temps in my C4 and in the fall the motor ran too cool. For the C5, I left in the stock stat and put in a Vinci switch. It turns on both fans at 208 and off at 201 in traffic. On the highway, my temps are around 192-194. Oil usually never goes over 210, but I don't run the car super hard either (track events and such).

 

I thought it was too low when I first warmed it up after picking the car up at Lingenfelter. I think the smartest thing for me to do would be to replace the 160 degree thermostate for a warmer one at least till summer. It's cool in NW Wisconsin even in the summer usually! It takes sometimes 2-3 hours for the check engine light to come on, (check original post in this thread). I'm stuck just S. of Madison at the moment waiting for weather to continue home. I've warmed up the engine and driven around town here several times, and no engine light!

 

Whether that's too cool depends on how you intend to use the car. If it's a cruiser, for looking cool , leave it stock. Chevy did a good job setting it up for this.

If, however, you race it, and modify it for increased performance, then that is not too cold a coolant temp. Making more HP means making more heat, keeping the coolant cooler gives you a bigger "heat sink" to get rid of that heat when you go full throttle. If you increase compression (I'm at 11.4:1), running the motor cooler will reduce hot spots which cause detonation. Running a LITTLE cooler than stock (in the 175 to 190 range) will also make a few more HP than stock, if you tune for it.

Downsides: The oil life monitor will tell you to change the oil sooner. Big deal, I change mine at 5,000 miles anyway, before the oil nanny tells me to.
Decreased engine life? Again, what's your intended usage? Race motors don't last forever, I've got 5 years on mine as modified, and I bet it'll go another 5 just as strong.
Increased carbon in the combustion chamber? I suggest that is a problem for cruisers, not racers. Even so, it's not a big deal to fix, even Chevy has a fix available.

Sorry for the long post, but when this issue comes up, everyone gets so polarized in their viewpoint, there's room (and reasons) for both.