Thermostat poll, 160 vs 180

[ltmark]

I could be way off base, but I have spent hours upon hours rying to get my '85 to run cooler...It was running at 230 in California (summer) in stop and go and to me, that's too hot! I don't care what the manual says! If the 160 opens a little sooner, than maybe it will run a little rich for a minute or so, but if it's 230 at the sensor, I can imagine what it is at Cyl #8. I have my aux fan sensor (that fits by cyl #8) wired directly to my main fan relay. When that sucker goes to ground, the fan kicks on!

Unless I'm causing harm (which I don't want to do), to me,230+ degrees is too damn hot?

 

[Rufus1050]

I went with the 180 when I changed mine. Been satisfied thus far...

 

[Im1ru2]

My 86 is stock except for the open air box & K&N, down here in florida mid summer,
it maxes out about 215 in heavy traffic.

Jammi'n Jeff

 

[TriTown]

Thermostat

You want the engine to get hot enough to remove any moisture from the oil. Sludge will eventually result. By all means use the 180 degree.

 

[wishuwerehere82]

Well don't go out in the winter because you are not going to have much heat.
But the worst thing about a 160 is the engine don;t heat up enough which causes (CONDENSATION) do i have to say anything more ?.

Funny you should say that. I just had a lond conversation with a buddy that just spent $250.00 to get his Grand Prix fixed. It was firing on about 3 cylinders and had water down in the spark plug boots where it was shorting to the block. He has a 160 degree thermostat for autocross racing and apparently has to pull the heads to change it. Two days later it was misfiring again thanks to winter driving.

 

[Mervin]

Cooling Questions

Okay I have two questions, my 85 was continually running what I felt was too hot last fall. With air temperature less than 10C(50F) it would still heat up to over 200 F sometimes 220 F. Over the winter I put in a relay to start the auxilary fan at 195, then turn off at 180. Since the car still had the original 195 thermostat, I changed that to a 180, otherwise the aux. fan would never stop as the new relay senses the temperature between cylinders 6 & 8. Just idling in the garage to get it up to temperature, everything seems to work as it should, the auxilary fan kicks in about 195.
Now the question, what temperature should the main fan kick in? Mine is controlled by the ECM. The Haynes manual makes it sound like the main fan doesn't kick in until 239 F. Is that right? Also, I'm assuming the auxilary fan is the one ahead of the rad and the main fan is behind the rad, closer to the engine. Is that correct?

 

[warren s]

Well don't go out in the winter because you are not going to have much heat.
But the worst thing about a 160 is the engine don;t heat up enough which causes (CONDENSATION) do i have to say anything more ?.

Well if you start up and hit the highway,. and keep driving on open un-obstructed roads that would be true.

As almost any Corvette owner has experianced it takes just a few minutes in traffic to send the coolant temps soaring. Condensation in the oil is bad, but does you oil temp stay the same as your coolant temp?

 

[maxwellgood]

Here's an interesting article on the subject. I not saying I agree or disagree but the argument to stay at 180 is compelling. I copied it off the following webpage:
http://www.wku.edu/~nathan.plemons/htmls/increase.html
[size=+1]160 Degree Thermostat[/size] - Next on the order of useless LT1 items is the 160 degree thermostat. GM made the LT1 engine run very hot, temperatures of 230 degrees are not at all uncommon. These hot temperatures promote reduced emissions and a cleaner burn. Research has also shown that engine wear is related to temperature and that too low a temperature can cause premature engine wear. The stock thermostat in an LT1 is 180 degrees, the only reason the car runs so hot is that the computer controlled fans allow it to do so. From the factory the cooling fans are not programmed to come on until the vehicle approaches 240 degrees. While the vehicle is moving temperatures are easily maintained near 180 degrees, the temperatures only climb when the car sits at idle. If one so desires the computer can be reprogrammed to turn the cooling fans on at a much lower temperature, it is possible to maintain a temperature of below 200 degrees with the stock thermostat in place. The question then becomes, why does the engine need to run cooler? Racers have long known that cooler air is denser than hot air, denser air means more fuel and more fuel and air means more power. So if the engine is kept cooler it doesn't heat up the incoming air charge as much and more power is made. The theory is sound and very much proven, but the LT1 throws a small wrench in the theory. Because of the nature of the LT1's reverse flow cooling system the intake manifold does not have coolant flowing through it. So although the LT1 intake still gets plenty hot, it does not vary with respect to coolant temperature nearly as much as a traditional intake manifold does. The result is an engine that is far less sensitive to it's own temperature as far as horsepower is concerned. I would not have believed this myself until I tried an experiment at the dyno. I iced down my intake until it was actually cold to the touch. I then proceeded to make back to back dyno runs until the car was very hot. From this experiment I found that there was absolutely no reduction in power output until engine temperature exceeded 230 degrees, a condition that will never occur as long as there is sufficient airflow over the radiator. As such I can say with certainty that a 160 degree thermostat makes no difference in power. I cannot prove the lower temperature thermostat increases engine wear, but at the very least it decreases your heater output in the winter.

 

[warren s]

As I said over and over again, between the fan switch and the 160, I picked 1 mpg and 2 10ths at the track. For less than $25 its a simple enough experiment that many an LT1 owner has validated.

 

[mattyg92]

i installed the fan kit where when the eng temp hits 195 degrees it turns on the low fan to cool it down to about 170

 

[Dons97]

I accidently hit 160 but meant 180.

The thermostat only sets the minimum temperature so it has no impact on what your car runs in the heat of the Summer, unless you have one of those cars whose cooling system can keep the car temperature that low. Mine can't.

There have been numerous posts about 160 degrees being too cold for the engine and creating excessive wear from longer warmup times and during cooler weather driving when the car runs at the thermostat temp.

I pulled this from another thread on the 160 degree thermostat.

This was even in Corvette Mag recently. I truly don't understand the whole debate here about this. 160 or 180? What's the big deal? It's the temp when the thermostat opens so what does it have to do with engine operating temp? If the engine wants to run at 220, a thermostat opening at 160 or 180 doesn't really make a difference does it?

I feel like I'm in the middle of an urban myth here.

I'm soooo confused.....:confused

 

[DAVZKAR]

coolant temp

I run a 160 stat and the power programer which turns the fans on sooner. I have no trouble producing heat in the winter. The lowest temp the car ever gets even in winter is about 173. On hot 90+ days it may see 189-190 at an idle in traffic. But once moving at highway speeds it will run at 173- 184. For a while I had the throttle body bipassed but hooked it back up this past winter .:cool

 

[DAVZKAR]

Coolant temp

Sorry that was my LT1 with auto .:cool

 

[DAVZKAR]

Remember heat kills HP and engine longevity.

 

[iron cross]

Which way do you want it. The use of electric fans use voltage, important in firing the cylinder and require the alternator to work harder. A 180 will keep the heat in and not require the use of those power robbing electrical parts. Net result, faster and quicker.

 

[jcs44]

160 has no value unless you reprogram the fans also.

JCS44
LT4 Vert, Triple Black

 

[ßill]

OK, I’ve been watching this thread since it started. Some of the theories advanced here are hilarious. If the cooling system is properly designed it will be capable of dissipating at least the amount of heat that the engine can generate. If this is true, the thermostat is the part that regulates the normal operating temperature. The thermostat is NOT a switch, it is a valve and throttles the flow of water to the radiator. Under normal operating conditions the thermostat is neither closed or full open, it will be controlling the temperature near its design temperature. When testing a thermostat I have found that it will start to open at about the temp indicated on it, and be full open around 10 higher. As far as manual fans, here is where I mounted my switch. If anyone knows its there, THEY ARE LOOKING WAY TO CLOSE.

 

[thirdtimevetteowner]

So, DAVZKAR, you are going for the 160? I bought one from Jeg's a while back, but haven't decided if the 180 would be more appropiate. Your thoughts on that? TIA.

Rich K

 

[thirdtimevetteowner]

Should It?

Rich K

 

[tigmaned]

gee al this talk about 160 and 180 as me thinking my gauge maybe wrong?? my vette had a 180 which i didn't know till i already got a new 195 stat. but my 86 vette still runs at 185 most of the time and i have never seen it go over 200? its a new radiator and hoses, so when i got the car i noticed a small leak at the stat housing so i got a new stat since i had no idea last time it was changed, auto parts said it calls for a 195 so thats what i got. and like i said it runs at 180 most of the time?? this morning on the way to work 175 most of the way? i am going to get our temp gun to check it out so i know my gauge is right??