That "brass plug" is a Bleeder Valve! Use a flat head screwdriver to loosen it off to allow the air trapped in the system to escape. Once it stops "bubbling" air that is, you can close it off again.

Ok on the 00 model its a hex bolt (9/32). Bled the air out. Car still seems like its running hotter than it should. I parked it in the garage and let it run and the fans did kick on around 205/210 and cooled the car back down to 200. Had it out this morning and even on open road it was never cooler than 195 (its about 70 outside). I was thinking it should run at 180....not sure what i'm doing wrong. Could my guage be off?

Okay, I think I've got your problem solved now.....The 180 T-Stat DOESN'T cause your engine to RUN at 180! It is designed to just OPEN earlier than the 195 does. Depending on your engine'* normal operating temperature, you may notice a slight decrease in it'* temperature due to the T-stat openning sooner than before. Of course on a hot summers day & stuck in traffic you will not notice any difference at all!

OK, I was infering from SilverBullets post that it did....

Stock fan turn on points are 215 degrees IIRC. If you are in slow moving heavy traffic or are stopped the temperature will rise to 215-220 degrees no matter what you have for a thermostat, because the radiator isn't getting any/enough air to cool the coolant with until the fans come on. Once you get moving the temperature will get down to around the temp the t-stat is rated for, give or take 5-10 degrees, assuming your cooling system is good enough to keep it that cool. To make a t-stat work to its full potential you will have to have your fan turn on points lowered to around the same as he t-stat. For instance, the fan turn on points in our GTP are I think 182 degrees (because we used to run a 180 t-stat). I have never seen the car run hotter than 185 because of this, even when it had the 180 t-stat in it. It has a 160 degree drilled thermostat in it. Once the car is moving it stays right around 162-165 degrees, but we also have a fan switch, so normally if we are going slow or sitting at a light we will turn the fans on once the temps hit about 160 degrees to keep it at 165 or cooler. We like it around 165 on the street, just because that is what seems to be a good temperature for performance while being easy to keep it that cool. We run it at about 155 degrees at the track, but it is a lot harder to make it run that cool than it is to make it run 165, since that is colder than the t-stat rating, but it makes more power so thats what we do.

Chances are your guage is off. Neither the guage in the SSEi or GTP are correct. The SSEi'* doesn't make any sense, because it is correct up until about 180 degrees, where it goes up to ~195 on the guage, then it stays between 195 and 205 until the car is at about 220 degrees, where it will go up normally from there. Basically it reads ~200 degrees all the time no matter what it is running. The guage reads ~200 degrees when the fans kick on at 215. The GTP on the other hand, just reads a little higher than what the number is. While the scan too reads 155 degrees, the guage reads 165 degrees. So it reads about 10 degrees high. I wouldn't trust the guage unless you want just a general idea of how hot it is running, if you want exact numbers you will need a scan tool or a digital guage.

Hope that helps.

Shawn

Relieves some of the anxiety i've been feeling....Thought I did something wrong. Guess I won't know for sure how cool its running till I get my AutoTap. Thanks for the info!

That makes sense. Even though my gauge reads 180 F, if I use a digital temp gun and point it at the rad or thermostat housing it reads about 170 F.
Good info on the fan turn on temp. 215 F Wow that'* high. Well maybe not, since the GM service manual says that 190 - 220 is the normal operating temp range.
When my fans come on the gauge is reading about 200 but I haven't taken a digital reading at the time. I have never seen it rise beyond 200 F or 90 C in all the time I've had it.
The coolant temperature must vary at different points in the cooling system. That is one of the reasons that ZZP recommends drilling the holes, so there is coolant flow even when the thermostat is closed when the coolant temps around the cylinder walls are much hotter than the temperature transducer is reading.

Sure wish I could how to get that damn Caspers high speed fan switch kit to hook up. It'* not adaptable to 2000+ engines, ie. it'* not a direct plug in like the older engines.

Okay, on this drilling holes thing. What size? How may?

1/16" is plenty big. Make sure to put the holes inside the rubber seal and get rid of any cling ons.

Side note. When I removed my 195 it had a 1/16" hole in it, but there was a bearing there to stop the flow. Why did ACDelco put a hole there only to have a BB there to seal it up?

Mine did also. I asked the guy at Autozone about it and he said it was some kind of pressure release that they put in all the new Tstats....funny the one they sold me didnt have it... Any disadvantage to drilling the T-stat? I didn't...wondering now if I should have.