Any Ideas?
 

As I was leaving today to make it home for Christmas the Monte decided it didn't want to leave. Soon as it got up to normal temp the temperature gauge dropped to nothing and the "Engine Hot: A/C Off" message popped up (it was like 30 out so I didn't have the A/C on anyway).

So something is preventing the flow of coolant. The upper radiator hose was hot but the lower was not. So I'm thinking it's probably the t-stat itself or some sort of electrical issue with the temp sensor.

Anyway, the car's at the dealer now, funny thing is that the guy wouldn't believe that I had a 3.9L he kept asking if I was sure it was an '06. I told him they've worked on it before there and that I've seen the engine in the actual car myself on more than one occasion. He responded by saying that they'll have to look at it because he didn't even know about the engine.

Kinda makes me wish that I had spent the money on new belts for the Porsche instead of on winter tires for the Monte.

garrett, i never had that problem, but last week i got a recall type letter in the mail stating that a power steering coolant line may leak or seperate! did you get one? i took it to a local shop and they checked it and said it was leaking but i should be ok for awhile, just make sure the power steering fluid is not empty, then i'll have bigger problems! i'm gonna wait til i have time to get it to a chevy dealer and then get it fixed! the letter said i have until feb 2011, yeah it said 2011!! let me know if you got that letter yet, thanks and goodluck with your 3.9, but are you sure it is a 3.9, LOL

Well imagine this, the dealer called me and said it'd running just fine at the moment. They're gonna do some more research to see if the t-stat had just gotten stuck. Said it had quite a few stored codes that they reprogramed.

I actually blew a power steering line last year Chris, that was the first time the car went to this dealer.

Definitely sounds like a stuck thermostat. Thermostats operate like this: A spring puts opening pressure on it at all times. Normally, resistance is provided to this spring by a contained unit of wax. When the wax reaches a certain temperature (the temperature rating of the thermostat), it melts, allowing the spring to open the thermostat. When the coolant drops below the opening temperature, the wax hardens and the thermostat closes back up.

Over time, thermostats go bad, and get stuck either open or closed. This definitely seems to be the case here. The classic basic test is the hand on the upper radiator hose trick. Should be a cheap enough fix.

Thermostats are stupid expensive in your car, I hope you don't have to change it!

Chibi, are you referring to the labor or the actual part? Looks like it uses a standard thermostat to me, based on a quick search at Advance Auto's website:
http://shop.advanceautoparts.com/web...erm=thermostat

$9.99...pretty average price for a thermostat.

I honestly have no idea how the procedure would go since I've never worked on a 3900, but I've done thermostats on dozens of other vehicles and it's never been tough.

I thought the thermostat on the newer Monte engines was a whole assembly that cost ~$75

Well the car is parked in Laramie, the dealer wanted $400 to replace the thermostat and the gasket. They said that the gasket gets gummed up and will cause the t-stat to stick and that's the most likely problem. This was the 3rd time it happened, and the 2nd in the last two weeks so it's only going to get worse.

Anyway, my mom came and got me today so that I'd be home for Christmas. I'll have to start looking into the thermostat, see if it's a normal one or some fancy unit.

$400 for a thermostat and gasket???? Holy crap!

Either Chibi was right and Advance's website is wrong, or that dealer is really trying to rape you. Either way, that's crazy.

Let us know what happens.