Thread: New 2004 GTP Comp G!

Good Day,

I just purchased a used 2004 Grand Prix GTP Comp G with 210,000km. I have also owned a 1981 Grand Prix LJ with 267 4.4L V8, and a 1998 Grand Prix GT. The 2004 seems to be in OK shape, but there are a few things that I know need attention. I have been looking through the forums and I was wondering if there is a search function somewhere.

I am looking forward to working on the GP and enjoying the ride.

Hi FlightSergeantRose
Another 04 Comp Group owner. Here were my surprises, being new to the Grand Prix:
1) The passenger side leaks water thru the A/C system and onto the floor. There is a deflector, GM 15794785, that installs quickly and stops the leakage. To change your cabin air filter, you will need to remove an reinstall this deflector.
2) The fan speed control module fails, probably due to the water sloshing onto it before the deflector was installed. When this happens, the fan goes to high speed, even without the key in the car. You can't just replace the module. There is a capacitor that needs to be installed in the module's wiring harness. Without the cap, the module will just fail again. There were two under my dash. Whoever did the job didn't bother to remove the first one, just plugged the new one in and left it hanging.
3) The factory paint job was pretty bad, and I have corrosion in several places. Look forward of the engine air filter, at the small bulkhead. No paint, lots of rust. All four jack points - same thing. And the rear bumper reinforcement - same thing. For the first two, I used POR-15 (paint over rust). For the bumper beam, I had it powder coated.
4) Engine oil leaks. I did the valve cover gaskets on my own. Look up a you tube video and you'll get thru it fine. I still have a tiny leak, but I'm not going any deeper.
5) Transmission pan. I grabbed a Dorman replacement with a drain plug, so that I would only take a fluid bath one time. I have done a couple of fluid changes since then, much simpler. I don't go for power flushing, too many horror stories of failures after power flushes. So I change xmission fluid by installments; about half the fluid stays in the works, so my method will never end up with "clean/new" fluid, but will get closer and closer, like an asymptotic math function.
6) Oil changes. It helps to crank the wheel all the way to the right before you start. You can reach in from the front of the pass-side wheel and spin the oil filter. This one's a compliment, not a gripe. Try getting your hand on a Gen 2 4Runner oil filter.

There have been other issues, but they are more in the general maintenance category, common to lots of cars.

Thanks for all the responses guys.

So far I have:
1) Replaced nearly all fluids (except power steering and supercharger, just topped it up. It was extremely low). Transmission and filter, oil and filter, coolant, and brake fluid.
2) Used 3M light restore kit on the headlights.
3) Changed coolant elbows.
4) Installed aftermarket deck and remote starter.
5) Replaced both front wheel bearings. Both rear calipers. Rear right brake hose, and e-brake cable. (This was needed to get the safety signed off) $1300ish in parts. I did the work.
6) Replaced front valve cover. Took it to dealer under recall. I didn't realize They would not reuse the filler neck, so now I can't use the engine cover

What's still wrong with it:
1) Left rear door lock doesn't work.
2) Creaking, velcro like noise coming from headliner just to the left and behind my head. Much worse in cold weather. Not as bad when it's warmer.
3) Leaking coolant through the lower intake manifold gasket (I believe, anyways). I've performed a coolant pressure test, nothing. Smoke test, nothing. There is still coolant sitting on the lower intake gasket after replacing the elbows and washing the engine. It's a slow leak, but I can slightly smell the coolant in the car.
4) Driver's seat has a bad tear on the left from someone rubbing on it too much getting in.
5) Passenger heated seat doesn't work as well as the drivers side, and the top LED for it doesn't light up. Bottom one works.
6) Transmission slips pretty bad under moderate acceleration shift. I think from 3rd to 2nd. Light acceleration and heavy acceleration is fine.
7) A few times, the stabilitrak inop warning has come on. It always goes away, but still annoying.
8) Trunk floor cover is really wavy. Is this normal?
9) Sometimes needs to turn over A LOT before starting. Sometimes it does it when it's cold, sometimes hot. Engine temperature doesn't seem to matter.
10)The DIC cover has a scratch on it. Bothers me.
11) Passenger dash panel has a heavy scratch on it.
12) Head liner above passenger has a cig burn.
13) Sun roof makes horrible grinding sounds when used.
14) Head liner had pretty bad stains all over, but especially in the rear.
15) Windshield weather stripping is missing in some spots and not installed properly in others.
16) Rear right door weather stripping has some gaps.
17) Front and rear bumpers have some pretty bad rub marks and scratching.
18) Paint peeling from the roof 'weather stripping'(?). Not sure what that is called. It's between the door and sun roof.
19) Power steering doesn't work that well. Sometimes need to use a fair amount of strength to turn the wheel. When it does this you can hear the pump working hard.

The only thing really annoying me right now is the headliner noise and rear lock. The engine runs good and has a lot of power. I had a 99 Trans Am, 6 speed manual, that I had for 11 years and just sold a few weeks ago. The GP is a major step down in car condition, my T/A was in excellent condition, but I like the abundance of power with an automatic. I can also drive it in the winter and not have it take up my garage space.

It has a lot of problems, but I am a decent mechanic and can learn some new skills while I slowly replace and repair everything. The young man that I bought it off of lied to me about its condition. I had to drive 4 hours out of town to get it and it was -30C, so when I drove it around the transmission didn't act up until after I bought it and the outside temperature warmed up a bit. I also thought it was in better condition since it was his daily driver. It's the first bad experience I've ever had in buying a used car. Living in an isolated community, I couldn't get a GTP in my town. I had been looking for months. Had there been one in my area, I would have had it looked over much more thoroughly. I'll be more careful next time.

I'll have to dig some pictures out of the closet. I had it before the days of the digital camera!