Very Interesting! you finally made it clear to me. We have scorching humid/hot summers in Montreal.
I am going to find a 160 t-stat right away!

 

If..... you drive your car in the winter, a 160 degree thermostat will give you luke-warm heat. I installed a 180 degree thermostat and retuned my fans to come on at 195. My average temp stays around 192. I have some questions regarding the earlier reports of temps. in my operating range with a stock thermostat and fan settings.

 

wrong thinking , you neerd to adjust the fans ,, a 180 will not allow you to take your fan temps down to 180... the only way to do it is change out the stat, you do not want to run your car in the winter 30F with a 160 stat, the car will nover reach the proper oil temp and you will have premature engine damage.. running the oil at 160 is a killer the oil needs to see 200 + at constant run times.

 

i live in south florida, and you have described almost perfectly the behavior of a C5 during the summer months. the fans will kick on appropriately and the temp guage will run between about 192 and 225 or just a bit more. it's not the end of the world. the car was designed to work that way.

 

there is a re-flash from GM available. I got 6 done last sumer. (the primary reason for the re-flash was the gas guage issue - but there were a couple of engine management software changes as well.)

 

There is no problem what so ever with running a C5/6 with a 160 stat in cold weather, and you will NOT have lukewarm heat. As the driver, if you did not have a gauge in the car you would never know there was a difference.

What lowering the stat does (with a tune to lower fans temps accordingly) is it keeps the PCM in a more aggressive state. Once the pcm see's temps over 200ish, the car starts pulling a fair amount of timing and richens the A/F to keep the car from detonating. Many people look at Nascar cars that run hotter because it makes more torque and think it is the best for their street car, but race cars run on race fuel so they do not have to worry about the detonation problems of pump gas.

So in a nut shell, it's all about suppressing detonation with pump gas, and retaining as much power as the car can produce all the time.

I hope that helps.

 

Sorry Doug, I beg to differ with you. running a 160 stat in northern jersey when the ambient is 20 degrees F will in fact effect the coolant and ultimately the oil temp. with the stat at 160 and the outside air at 20F, the coolant will stay at 160 F, and keep the oil temp well under 190. Oil temps have been known way back in 1997 to be critical in the longevity of these motors . It is so critical that its a key flash point in the OLM system to flag high viscosity levels in the Algorithm ... running a C5 with its tight tolerances @ 180/190 F on of valve train and associated parts... running these cold oil temps creates shear and cause thermal breakdown of the additive package. cold starts and cold oil temps make for a very unhappy motor.these motors were tested and designed to 200,000 miles.. running the coolant and the oil temp too hot is much much better than running them too cold...thats why the 190 stat and the algorithm in the OLM. We saw what cold oil did to the test mules used way back them...and for this reason the OIL Life Monitor was coded.

 

ET has spoken!...isn't it great to get an answer like this from one of the engineers that helped developed the c5
Bill

 

Thanks, that answers my questions with the exception of these two. Do the fans operate in two modes, low speed and high speed? In other words one is not the low speed and the other the high speed, but both have two modes they can operate in. The second question is; even with the 190 t-stat, a resulting 230 degree temp on a hot Florida afternoon is not detrimental to the LS1?

 

Lots of dust bunnies collect in hot and dry air like that in Florida.. its important to do maintenance on your AC compressor and the Radiator which sits 3 inches behind it... As far a 230 F.. its within the design spec. here is how the fans work

Depending on model year
01-04
The low speed cooling fans are turned on when the coolant temperature reaches 108°C (226°F). They are turned off if the coolant temperature lowers to 104°C (219°F). The high speed cooling fans are commanded on when the coolant temperature reaches 113°C (235°F). they are turned off if the coolant temperature lowers to 108°C (226°F). When the A/C is on and the coolant temperature reaches 85°C (185°F), the low speed cooling fans will be turned on at vehicle speeds less than 56 kPh (35 mph).

For early model years:97-00
Low speed fans come on at 219,high speed fans come on at 228,low speed with a/c on...
Both fans have high and low speed capabilities
I hope this helps ease your mind... This is a solid design for this particular platform. Like many other things with this car, the design was ment to hit a certain target market, with a very specific budget, a target weight. A better cooling system could have been designed but in order to deliver this car at the target price, all project managers had to stay within their particular budgets. Just a little insider here.. I designed one part for this car with two defferent options.. the cost to manufacture of the second design cost an additional 0.05 cents a copy. there are eight of these in every C5... making the cost over the original design 0.40 cents per unit... the second design which was better was shot down because control of the budget got us this car at the target price..

 

Thanks again that answers all my questions. And yes I learned the hard way that lots of debri can accumulate on the radiator. At least monthly I clean out the area of grass, weeds, and on occassions small lizards!

 

Well sorry back Evil,
but you engineered STOCK cars, we engineer high performance cars, and high performance cars break down from detonation of pump gas WAY before an oil temp issue at a temperature level that the car is hardly ever at. A 160 stat will never have the car run 160 degrees in a Corvette either, but more importantly, most Corvettes are parked in 20 degree weather. Especially high performance Vettes.

The number one cause of engine failure coming threw our doors over the years is broken ring glands from... you guessed it, the detonation that we are suppressing with cooler stat. I have had next to zero failures from an engine that is simply worn out. Some from the road race guys, but then it's generally valve train failures leading to catastrophic damage. That's "real world", not a lab test.

If someone was looking for super longevity of a non raced, bone stock car, we are on the same page.

Now lets discuss the low oil temps of the C6Z dry sump..

 

Did you mean to say "most Corvettes are never parked in 20 degree weather"

 

You apparently do not live in a salt covered winter area. Many of the Vettes coming here in the winter are trailered for that matter, to keep the salt off of it.


Well I generally never go into threads like these, simply because I do not have time to debate these things, but I was asked to. If you feel running hotter and letting the knock sensors do their thing is the best option, by all means, go for it! I know what I see on the tear down of 100's of engines, and I know where I will direct my customers, and my warranty coverage to.

 

Doug I was not questioning your knowledge or experience. In your original post you stated "most Corvettes are parked in 20 degree weather" and I was just wondering if you meant to say that "most Corvettes are NEVER parked in 20 degree weather" that's all.

 

Doug I do not want to back peddle here, I know how detonation can destroy a motor, A high performance motor design always has issues with too much heat. We designed knock sensor to retard timing for that one or two times you get the wrong gas, lug the motor in the wrong gear, etc. I address issues with the car as it come out of the box... Thats why I do not offer any input on engine mods, or step into anyone's post on tunning above the specs of the stock car... But let me tell you this, you are wrong on the 160 stat and 20 degrees F. I have personally witnessed coolant at 160 F with a car using a real 160 stat in an ambient temp of 20 F on a freeway ( AC Expressway) doing 70 mph... I saw the test data of some of the original LS1 test mules when designing the OLM, and the effects of cold starts and and cool run cycles. Cold engine oil breaks down very quickly. Running with these issue for extended periods of time will take your 200,000 mile tested motor and take more than half its expected life., These are facts as tested with a stock motor. Winter can be a killer without proper focus on the right oil and the right coolant and oil temps... A stock motor has a sweet spot.. Not a performance sweet spot ( thats a completely different perspective ) I deal with 90% of Corvette owners who drive a stock car.

Bill aka ET

 

I thought you meant they are always driven in 20* temps so they are "never parked".


I think we are just viewing the same engine in two perspectives, which is why I stated that we are on the same page with a stock car that is not raced. (when I say not raced, I do not mean it has to be on a race track, just commuter driven like a normal car) With a performance minded customer, like many on this site, we change the oil more frequently then the DIC states, use better oil, and focus on getting the most performance from pump gas. In my experience that requires a 160 stat to sustain longevity of the engine.
I guess I deal with 90%+ of customers who are looking for performance, so it sets a mind set.

Thanks for your input.