Pontiac Grand Prix questions

[va3ux]

I'm considering a Grand Prix to replace my aging Intrepid. I like the thought of the bullet proof 3.8 engine and the fact that it gets mileage that is the same or better than the worrysome 2.7 in my Intrepid. And, I've always sort of liked the look of the Grand Prix. I really like Intrepids but the only alternative to the iffy 2.7, is the 3.5 which doesn't do all that well in the gas mileage dept. And fuel economy has become an important deciding factor.

Questions :

1) What is the difference between a Grand Prix GT and a GT2 ?

2) Are there any specific model years to avoid or favor ?

3)Any known issues or problems to look for when scouting the used car market for Grand Prix's ?

4) All comments welcome - positive or negative.

Thanks in advance....Phil

 

[Drew99GT]

I wouldn't say the 3800 is bullet proof at all; they newer ones have a history of intake manifold gasket leaks and upper manifold leaks, both leaking coolant into the oil.

But if you get them fixed good, they are very solid, powerful, and economical motors.

Also, for some reason, Pontiacs seem to have more electrical gremlins compared to other GM models, even on the same platform.

 

[ekpolk]

I would act relatively soon if you decide you want one of these new, as this model is on its way out. Ditto on the classic 231/3.8/3800 V-6; if I understand correctly, 2008 is it's last year of production too.

As to your questions, I don't recall the specifics betwen GT an GT2. It may be the blower -- I do recall that last year, there were three sub-models (vice this year's two), the middle of which was the blown GT. But I thought that in earlier years, some GTs had a blower and some didn't. Sorry, not much help there...

As for model years, I'd recommend the newest you can find. These cars will depreciate very quickly early, after which the curve flattens out. In short, a good 07 or 06 shouldn't be that much more than an 05 or 04 in similar shape.

The oil filler on the 3800 allows for a good view of a relatively wide area of the top of the head. Open it up to check for varnish or sludge on any candidate car. Also, the filler neck used on some versions can be unscrewed just like the cap (all plastic -- yech...) allowing an even better view. Do take advantage of this capability.

I had the Buick version of this car, a 98 Regal GS. Actually, I had two, the first being swapped for a second at ~10k miles in a deal I struck to avoid a lemon law action. But anyway, mine developed some pretty bad body rattles, so I'd recommend driving a candidate car on a bad road to see how solid it feels and sounds.

Overall, these are good cars, and I think you should be able to find one that suits your needs.

 

[va3ux]

Originally Posted By: Drew99GT
I wouldn't say the 3800 is bullet proof at all; they newer ones have a history of intake manifold gasket leaks and upper manifold leaks, both leaking coolant into the oil.

But if you get them fixed good, they are very solid, powerful, and economical motors.


I thought the intake gasket problem was only on the 3.1, or perhaps on all the V6 but mainly for engines produced at the beginning of the decade. Am I wrong on this ? I have heard of the problem but admit that I'm shaky on the details.

Quote:
Also, for some reason, Pontiacs seem to have more electrical gremlins compared to other GM models, even on the same platform.


Thanks. I hadn't heard this before.

 

[wapacz]

the 3.1 and 3.4 you are pretty much guaranteed to have leak coolant. The 3.8 just have a higher chance of it happening then some other motors. Once it is fixed with a good gasket it is good to go.

 

[Drew99GT]

It's also the plastic upper intake manifold/EGR port that melts and induces coolant. It's happened on all the 3.8Ls we've ever had.

 

[mstrjon32]

My mom has got a 2006 Grand Prix that yields something like 28 mpg in her daily use. It's quite an economical car.

 

[dwendt44]

The base model of Grand Prix is just that, base.
Used to be the SE, GT and the GTP(supercharged).
Newer ones are SE, GT and GXP(V-8).
GT is the one I've had, on my fourth GP. I have an 08.
The production line has stopped in late October.
The G-8 will replace the GP and will be out in spring.
No real problems on newer style GPs.
The 3800 is bullet proof, the intake gasket thing is rare on this engine. The supercharged units use the same block as the N/A engine some you know it's hardy.
The 08 model year will be that last for that engine; it's a 90° engine and too 'wide' for new chassis's.
I've gotten excellent mileages on mine, mostly highway miles.
Highest was an amazing 38 on a couple of occasions.
Generally in the low 30's most of the time. (highway).
Like many brands these days, options are bundled in packages, so the more 'goodies' a car has the better.

 

[Drew99GT]

No, the intake gasket leaks on the 3800 are not rare. Look at UOA results here. Neither is the melting EGR stove pipe in the plastic upper intake manifold. It's something that is basically guaranteed to happen. You may not know it's an issue, but it's there. 99.99999% of people will never know (until the coolant tank runs dry).

Cripes, my moms friend with a Bonneville stopped by last month and said her car was running hot. I popped the hood, coolant overflow was dry and rad was down about 6 inches.

Sorry, that is not bulletproof!!!

GM 3.1L, 3.4L, 3.8L, 4.3L, 5.0L, 5.7L, and 7.4L mills all are leakers.

But once you get them fixed with the Fel pro gasket set by a competent mechanic, I'd say they are bulletproof. Ballsy and economical.

 

[Merkava_4]

Quote:
No, the intake gasket leaks on the 3800 are not rare. Look at UOA results here. Neither is the melting EGR stove pipe in the plastic upper intake manifold.



There is a new improved upper intake manifold available that has a steel bushing installed in the hole where the EGR tube goes through and the EGR tube itself has a reduced diameter for providing an additional air gap. Problem solved.

There are improved UIM and LIM gaskets that have aluminum backing strips that eliminate the past problem of the gaskets becoming deformed under the presence of torque. Problem solved.

The Buick 3800 V6 is on the top 10 list of best passenger car engines known to man.

Auto Parts Network

 

[MrCritical]

The Grand Prix is built in base model only now I think.

The plastic intake has been gone since 2003.

The GT2 is the code for the upgraded options add.

I had an '04. When I traded it at 71k, the transmission was whining, the power steering was whining and the air conditioning was whining. It does have more problems than other GM models, for what reason I don't know.

 

[GMBoy]

All the talk of the intake manifold issues make me consider myself lucky. I had an 03 Grand prix GT, sold it to my cousin in 2005 with 34,000 miles. He now has 101,000 and still no manifold trouble. He did do a coolant flush around 85,000 miles since he had to change the water pump anyhow. I'm gonna get him to do a used oil analysis to be safe on the next oil change.

 

[ekpolk]

Originally Posted By: MrCritical
The Grand Prix is built in base model only now I think.

The plastic intake has been gone since 2003.

The GT2 is the code for the upgraded options add.

I had an '04. When I traded it at 71k, the transmission was whining, the power steering was whining and the air conditioning was whining. It does have more problems than other GM models, for what reason I don't know.


Per Pontiac.com (checked this morning), the car is still available in two configuratons, the base model, and the performance model with the 5.3L V-8 (very similar to the current Impala SS).

Problems such as you describe are not unique to the Pontiac variants of this platform. As I mentioned in my earlier post, I had two 98 Regal GSs, the first taken back and swapped for another as an alternative to a Lemon Law action; the second I put up with for a couple years and about 50k miles, IIRC. They were great cars in some respects, very irritating in others.