Thread: General problems? No clue about GM's...

So I bought a 2000 Grand Prix SE with 149k miles on it last fall for a "higher" mileage vehicle. I work for Ford as a diesel tech and I know very little about the engines in these Grand Prix's. I have a few questions/problems with my car...

1. Last January I replaced the thermostat because the car would warm up, but the air blowing out of the vents was never warm enough even with the heat cranked. Now, however, the car tends to run HOT when its not running at a constant RPM. Like we're talking 215-220 degrees. Any kind of stop and go traffic, or even driving for extended periods of time in the suburbs with stop lights and what-not makes it happen easier.

2. Relating to my issue above, when engine temp increases, my transmission acts up. From a standstill, 1st gear will wind out till RPMs won't increase anymore (not near redline) and give a HARD shift into 2nd. Same for 3rd and 4th. This only happens after the engine has warmed up to where I stated above.

3. Another heat/transmission issue I've encounted (getting fed up at this point already lol). When the engine is at that hot temp, if I put my foot into the pedal too much (not excessivly), it will studder almost like the tranny is slipping, but the tachometer is effected as well.

4. The other day I pulled my car into the shop at work during my lunch break and I was just doing an inspection to kill time and check the front-end suspension when I noticed the crank pully "wobbling" at idle. When I increased the throttle, the shaking stopped. It isn't throwing engine timing off at this point and I can't feel any vibrations in the car. Is this something I need to be worried about?

I know that head gaskets are a common problem on these and I expect to have to replace it at some point. But is there any information/experience with the issues I have come across thus far? I just want to TRY to make this thing last as long as possible... Any input is GREATLY appreciated! Sorry for the long post...

Andy

Can a mod please move my thread...? I really need some insight from some "grand prix gurus' and apparently I came to the wrong place.....

Yo Andy!

First, have you checked your radiator to see if some of it is getting clogged, i.e. cold spots? Is the lower rad hose the same temp as the upper? Check the lower portion of the rad with an infrared themo and compare it to the top. This could be why it is running hot.

Is the cooling fan coming on at these temps? Do both cooling fans come on when the AC is truned on?

Are your heater hoses collapsed, thus restricting flow to the heater core?

As for the pulley, on some LS1 Vette engines, the crank pullies rubber isolator fails and the pulley whobbles and will eventually fall off. The only fix is to replace it, sounds like yours is going south too. I would replace now...

As far as the studdering at temp, you suspected trans but the engine stumbles too, do you have any codes set? What is your fuel pressure? Have you changed out your fuel filter? How many miles are on the car, enough to justify new plugs?

Related to miles, have you dropped the trans pan to change the fluid and inspect?

3.1L, 3.8L, or 1.8L, does not matter, general diagnosis is the same. I do not need to be versed on a 3.1L to help, no one really does for that matter...

Sorry brother! I've been busy as hell with work and side jobs and what not. I got the post on my BlackBerry and read part of it but I haven't had a chance to get back on here much less look at my GP.

I thank you TONS for the input I plan on looking at it this weekend. I'll let you know what I come across!