Drilling a single small bypass hole has a HUGE benefit in allowing air to purge out of the system efficiently, as well as a little extra flow when open or closed. Some drill more than one hole.

Cooey, there are very specific reasons most of the members of this Forum run the 180. Your advice is similar to telling people not to tint their windows, because they came untinted for a reason.

EMISSIONS requirements are why GM standardized on the 195° thermostat. But at the same time, we've never had a member fail emissions with a 180. Your car will operate slightly cooler as long as the car is in motion or the fans are on. Lifetimes of the fluids will also be improved. Efficiency and power will be slightly improved as well, gasket life maybe also. And you may extend the life of your L36 UIM if you have one.

My question centers on that right there. I'm not as concerned with performance (making it high performance, that is), its a 11 year old car with close to 130,000miles. When I tear into this UIM/LIM repair this weekend, I want to do everything to insure that I won't have to do it again, or at least soon. That is the basis of my question.

The other thread on this is also helpful.
http://www.bonnevilleclub.com/forum/...ic.php?t=72304

Our motor is designed to run optimally within a certain thermal window. The reason the 195 is used is a hotter engine burns gas better and thus is more economical; less waste emissions resulting. So when one says meeting GM emissions standards that is not enough. Emissions are reduced when fuel is used more completely. As far as I can tell you want your engine as HOT as you can get it without pre-ignition. Efficiency of the engine goes up the more heat the cylinder heads retain - up to the point of pre-ignition, all other things being equal. So you want it just cool enough so that the PCM does not retard the timing. A cool engine draws heat out of the combustion process - less vapor (combustion) pressure, less ability to do work (push the piston down). Not to mention the possibility of oil contamination from unburned fuel (due to lower temps). Pre-ignition can be reduced also by using higher octane gasoline which of course the */c engines should use. (I am using a 90 octane 10% ethanol fuel without knock occurring)

Many mistakenly think that all there is to decreasing temperature of the engine is to decrease the temperature rating of the thermostat. If the cooling system cannot keep up with the heat the engine is generating, a cooler thermostat will help precious little. The second misconception that if some engine cooling is good, more must be better. Again, most engines run optimally at the recommended factory temperatures. Significant departures from these recommendations are most often counterproductive. The temperature is critical to the efficiency of the burn of the fuel and the tolerances of the motor itself. 180-195 degrees F is common on conventional engines. Modern motors see higher temperatures (205-210F) , mostly due to fuel and emissions efficacy.

So then:
Hotter heads promote detonation.
Hotter heads rob less heat energy from engine combustion, increasing combustion efficiency.
Hotter blocks reduce oil contamination.
Hotter/thinner oil reduces friction losses.

I see where one might use a pin hole or 1/8” hole or whatever size for “in-use” air bleeding from the coolant system, but if you are bleeding air from the system properly when changing out a thermostat then the hole is not mandated I’m figuring.

While most members of this forum might use a cooler thermostat, I would guess that most bonnie owners don't think about it and use the factory 195.
But probably as was said in another thread it really doesn't matter which one you use; your 3800 will go at least 200k mi.

Cooey... As I haven't gotten involved in this thread before, I'd like to take a moment and point out some of your misconceptions. I'm not interested in your retort, comments or further suggestions and will not be returning to the thread to view them. My reasoning for handling you like this is your flagrant disregard to consider or view proven information.

Your supercharged motor is running on 90 octane with no KR. Have you checked the timing tables? Why do you ask? Because your pcm most likely has you running on low octane tables, making minimal power and using more fuel in the process.

In the NA motor a higher combustion temperature increases the EGR temperatures and heat cracks the thin wall between the cooling passage and EGR stovepipe much quicker. This then fills the motor with coolant. The supercharged motor does not get effected by this and therefore..you won't get he pleasure of destroying your motor with your advice, only someone else'*.

Somehow I feel that you would tell everyone here that the lower intake manifold gaskets don't degrade in the Series 2 engine running Dexcool as well. Lemme give you a wake up call pal....you've thoroughly pissed me off and now you get to hear it.

Lower intake manifold gaskets on Series 2 degrade, dexcool speeds this process.
An NA motor as well as an SC'd motor benefit from running 10-15 degrees cooler.
Our cooling systems can keep up perfectly fine with a 180 T stat. If yours can't.. clean the system...it'* probably plugged.

By running your 90 octane fuel, you might think you have no KR...if you scanned, which I am doubting at this point...you would find your timing is most likely in the single digits. That'* why a Yugo passed your supercharged car yesterday.

Pssst...is there a mechanical problem here? I'm thinking this should be in Gen Chat...

Dude, relax. He'* got some legitimate points...a lot of the same ones I brought up in my thermostat thread.

I don't understand why people are getting so heated over this...there are some good questions being asked which nobody cares to answer without complaining that we're not acknowledging "proven information". I joined this forum for educated/curious discussion...anyone else feel the same?

I hear people talking about the great gas mileage they get with 180 degree thermostats...but no comparison to gas mileage with 195 degree thermostats. Nothing proved!

I hear people talk about ranges of thermal expansion and their effect on wear. At low temperatures the engine components haven't expanded as much. At high temperatures they expand too much. It seems the happy medium has been placed arbitrarily at 180. Maybe 195 is ideal? Nothing proven!

I hear people talk about hotter thermostats being strictly for emissions. As far as I know, none of them work for GM. Nothing proven!

It'* not that I don't believe you guys...I do! You have far more experience than me regarding the 3800. But the reason I'm asking my questions, is I want to know why it is the way it is. I'm looking to see if anyone has data they can compare...or any real comparative observation to share. I'm after the explanation more than the answer, but the answer is all I'm getting.

Hmmm?