I know alot of us spend countless dollars trying to keep our engines running much cooler than they did when they were driven off of the showroom floors. Example: mine runs approx 197 degrees at highway speeds and 225 degrees in town with the A/C off. I hate seeing 225 degrees so I normally leave the A/C on auto so the primary cooling fan stays on and the temp normally doesn't get much above 200 at any time. GM has designed these cars to run much hotter than any of their other cars for some reason so if we change thermostats or turn the fans on quicker than designed are we doing hurting the performance or longivity of the corvette?

 

The basic reason GM made the 350 to run so hot is for emissions. On the other hand, you don't want to run too cool (say below 160) as that would increase wear on the motor. Most guys like to run around 200 as an average.

 

Hard to say, but I don't think that the OEM design is causing any problems. I can't remember any postings here, on the Forum, where someone's engine was destroyed because the engineering necessitated high coolant temps. If you review the OEM Bulletins or peruse the NHTSA web site, there aren't any fixes or listings showing that coolant temps are a problem. Engines seem to be lasting just as long, if not longer, and if Mom & Pop's SUV self destructed due to high temps, I'd think someone would demand a fix.

As to lower temps, I don't know of any definitive studies showing they're beneficial or add to longevity. It would seem that you might get a richer fuel mixture leading to oil dilution, an overheated convertor and mryiad of other problems that plagued carbureted, pre-smog motors, but again, I don't know of any definitive studies.

 

As long as my coolant is less than 230 in town or 20x on the freeway, I'm happy. What I really want is my oil temp above 212 so any moisture is boiled off. Sure, there is a lot of support for the "cooler is better" school of thought, but *too* cool is a bad thing.

 

Somewhere between 180-220 seems to be good operating range, of course higher or lower for short periods is probably not harmful. Main this is to get the oil up to temp.

 

Ultra cool temps have their place in specific, limited use applications, such as the race track, auto-X, etc. Most engines make more power at lower temps, but longer warm ups and too low operating temps are NOT good for longevity. Your temps sound perfect.

RACE ON!!!

 

Having it run too cold, with dino oil, is not a good idea. Sludge builds up in the pan, and the contaminants that get stuck in dino oil end up eating away the bearings. (this is one reason to use Mobil) Fuel mileage is lower for a cold engine, a bit. When I went back to LSU from SC in January, I got only 22mpg. Normally I get 24. I came back yesterday, and got 22.2 running the AC the whole time.

Running too hot all the time isnt good either, if you notice your plugs, youll see what a constantly hot-running engine does to them and all electrical components for that matter. Also head gasket failures.

I decided that running 220-230 everyday in the SC heat was too much, so I fixed it, with a 160 and reprog. chip. It wont get over 200 (coolant) unless I run the AC.

We're designed to run hot merely for emissions, yet the L98 tends to make its very best power when its cold, and I have several track tests from old magazines that show it. LT1 likes to be a bit warmer from what I can tell, for optimum power. NOx is cut down when the engine is warmed up with EGR, and Cats need to be hot to start fixing the exhaust gases.

 

http://performanceunlimited.com/illu...ermostats.html
http://www.carnut.com/ramblin/cool3.html

180 t-stat with fans operating around this point (ie, on at 195/200 and off at 175/180) is the sweet spot for STREET performance vs. longevity.

 

Just for comparison, I thought I would share my temp mod results. My 1989 vert was running between 225 and 235 in Phoenix when I bought it. I put in a multicore radiator and 180 thermostat, but did not switch the fan controls. In Phoenix, it then ran between 195 and 225. Then I brought it to Seattle (in the great NorthWET), where it runs between 180 and 200. Performance has been very strong, and overall I was pleased with the results.

 

You shouldn't run a street engine below 180F because of sludging up the oil.

The high temps that the General gave us won't do any immediate damage, but organic stuff (rubber and plastic) deteriorates roughly twice as fast for every 18F increase in temperature. Your hoses, and plastic bits on the engine will last longer if you keep the temps down closer to 200-210 max.

You also probably don't want to wear your fans out prematurely by running them nearly all the time. Fans on at 210F then off when it drops back to 205F would be nice compromise for street operation. If you program your fans seperately, then fan 1 on at 210F and fan 2 on at 215F would be a good combo. I don't see any reason to set the fans for a higher temperature for street driving. If you set them lower they will run a lot more and wear out faster.

 

My stock '96 LT-1 is running 200 on the highway and 220 in stop and go city traffic. I've only had the car a few weeks and have been wondering if it was in the 'normal' range. Sounds like it is.