Bonneville owner considering Grand Prix has some questions.

[harrydunn]

Greetings--

Long-time Bonneville forum member who is considering dumping the 4-door Bonny for a '97-'03 Grand Prix GT 2-door.

I have a couple of questions regarding the GP. My 2000 Bonneville has an annoying design flaw that causes highway vibrations that I've spent way too much money on trying to solve. There is a control arm TSB "fix" on it with limited success so I'm not going to go that route. I've tried everything else to no avail. At this point, I'm looking for a smooth-riding car--hopefully the GP will fit that bill.

So, Question #1: Do the Grand Prixs in the '97-'03 range have any vibration problems that cannot be solved like the Bonneville? Other than a wheel out of balance, etc? This has been so annoying to me and is why I am selling the Bonneville with only 50K miles on it. I do not want to buy the same problem.

Question #2: I've heard loads of issues with the transmissions crapping out (which now has me worried about my Bonneville transmission since they are the same). Are most of the problems just associated with a bad Pressue Control Solenoid? Would anybody care to elaborate?

Question #3): I would be extremely appreciative if anybody would be flat-out honest and fill me in on any potential problems these cars routinely encounter. :th_winking:

I know it can be annoying to have a noob asking questions about a car that he doesn't even own yet, but I've got to make sure I don't run into the same problems as I have now. Mainly, just the highway vibration!

Thanks!

 

[justwhisen]

well my car has the vibration you speak of. but I also need new wheel bearings and a half-shaft. the vibration hasnt always been there.
as for as the trans you can rebuild one your self and make sure the thing is built right or you could have trannyman (aka Dave) build on for you.
I have also noticed that many of the GP's and monties have a upper door moulding issue where it rips at the back corner where the door meets the roof.
but all in all I love my ride. the only other car that has left a good impression on me was an 83 olds cutlass.

 

[harrydunn]

Funny you should mention the Cutlass. The car I had before the Bonneville was a '96 Cutlass Supreme Coupe that was the best car I've ever owned. Smooth as silk. Very hard to find them now in good shape with low miles.

 

[BADAZGTP]

To be honest, I've owned my 97 GTP since 99 and wouldn't trade her for anything. Have never had a vibration problem. My tranny went out, but that was due to the rubber tranny line busting on my wife and burnt up the clutches. Car had 90 thousand + miles on it and still pulled just as hard as she did when I got her. she sat for 2 years while I was deployed, got bacck swapped the tranny, did a fluid flush and drove her for over a year. the only other problem I had was about a month ago when the ICM went out. 130 bucks and she's back haulin' butt again. I'd say go for it man.

 

[DanGTP]

I love my GP! The only vibrations I get are when my front end is out of alignment due to replacing tie rod ends. My trans has 113k on it and has never been rebuilt (just regular fluid changes).

 

[Blown97]

Typical problems/bugs I have either had or seen others have:


Body/Interior:

1. Blower motor resistor

2. Power window regulators

3. Tail light separation

4. Head light lenses fog/separate (stock)

5. Water deflector separation (under cowl)

6. Drainage tube blockage (moon roof only)

7. Water leakage in trunk (spoiler only)

Chassis/Engine:

1. Tie rods (stock ones are not greaseable)

2. Valve cover gaskets leak (there is a recall on the front one, even though they both end up leaking)

3. Intake manifold gasket (made of plastic :th_shakinghead1:, get the metal ones)

4. Intake manifold cracks (N/A 3800s only)

5. EGR tube cracks (intake side)

6. Various vacuum leaks

7. Power steering pump

8. Possible cooling problems due to GM Dexcool mudding up the system

NOTE: Not all w-body cars suffer from all of the problems listed above. This is just an incomplete list of common things that may need attention during the life of your w-body. With all that said I would highly recommend getting a 97-03 Pontiac Grand Prix GTP. Good luck on your quest in getting yours!! :th_thumbsup-wink:

 

[harrydunn]

Wow, seems like everybody is defintely saying go GTP rather than naturally aspirated. Besides the obvious reasons :th_winking:, any other reasons mechanically speaking that a GTP would be better in the long run than a N/A GT model?

Can anyone give me performance numbers for a stock GT vs. stock GTP? 0-60, etc...?

Thanks.

 

[Sabrewings]

Don't get me wrong, I love my L36. Peppier down low than a L67. It'd be even more so in the GP GT since it has 3.29 gears as opposed to the L67 2.93 (or my 3.05). No real mechanical differences in terms of reliability in normal use to speak of. I've driven stock L67s and even fairly modded L67s and was underwhelmed compared to my modded L36. It was better, just not as much as I had thought.

But...

But. If you want to mod, it's easier to already have forced induction than add it later. The L36 takes to mods decently, but I feel you'll see better gains mod for mod on the L67 because it's force fed. I'm going supercharged myself relatively soon. It's just the way to go if you want more serious power. Plus, as a consolation prize to having lower 2.93 gears, you do get the HD differential to take burnouts better. The L36 would have the non-HD which can fail after excessive burnouts.

So, with all that in mind, it's up to you based off what you want and what you're going to do.

NOTE: Not all w-body cars suffer from all of the problems listed above. This is just an incomplete list of common things that may need attention during the life of your w-body.

Not quite. Montes nor Impalas have tail light separation, spoiler leaks, or valve cover gasket leaks (probably because L67 wasn't offered until 04 when the VC gaskets were supposedly improved with the introduction of the Series III motors).