1999 GTP New Owner

[Impala131]

(Essentially copied from my other thread.)
Hello all, I live near Grand Rapids, MI and have just bought a 1999 Grand Prix GTP. I am ecstatic. The car is in amazing shape, about 230,000 miles, and was great during my test drive. I'll be getting it from somewhere in Big Rapids next weekend, when I have the time to drive it home. The car seems to have been maintained very well, lots of documents and receipts, feel good about my purchase so far. (Pics later, I promise.)

I'm a do-it-yourself-er, not a master mechanic but I've got some experience working on 3800 Series II powered vehicles. This is my first of the supercharged variety, however. I'm joining this forum straight away because I know there are many of you with a lot of experience that could definitely give me good advice and educated opinions, which I certainly value. Always helps to have a knowledge base! And maybe I'll make some friends too.

Anyway, a few questions if you don't mind. This will eventually be my daily driver, but since I already have a dependable DD, I want to take my time and do the proper maintenance/precautionary work before putting it on the road. And if you were wondering, it has indeed been fixed as far as the L67 engine fire recall goes.

1. It has the original motor and trans. It never had an issue with the LIM gaskets, so they were never replaced. At this high mileage, should I go ahead and replace them?

2. If I decide to replace the LIM gaskets, what else should I do at the same time? For example, should I replace the head gaskets too and have a look at the pistons/heads? (Lets assume that aside from regular oil changes etc., it hasn't had anything done for the last 50,000 miles)

3. What other parts should I probably replace either way? I'm guessing there is supercharger related parts that might need replacing that I'm not familiar with.

Thanks for your responses, guys. I should have plenty of time to get this car right where I want it. I'm not really interested in mods, 240hp is enough for me, but if you can suggest anything that might be smart to add while I've got the engine apart, go ahead and suggest it. I'm sure you have lots of great ideas.

[jwjones]

"If it ain't broke don't fix it" Congrats on the new car!

[dsmuts]

If you see signs of the lim gasket leaking then change it. Your head gaskets will never need changed. Welcome to the site.

[Impala131]

I also have a concern about the tranny. On my test drive, the shifts were fine. The fluid looks reddish, and obviously needs changing, but no metal bits or brown. At 230,000 miles though, I'm kind of worried about breaking something. Aside from maintenence, what can I do? Better fluid? Shift kit?

[redgtp97]

change the lim gaskets if they havent been done. Leave the head gaskets alone. As far as the tranny goes you can drop the pan and replace the filter and then refill what was loss with new tranny fluid. A lot of peolpe advise not to flush a high mileage tranny, but a pan drop/filter/refill usually wont hurt anything. i did mine this way at 125,00 with no issues

[Iceman6669]

Welcome to the site fellow GR person.... Drive it till it breaks... The LIM should be done soon.... The tranny will prolly start crapping out on you in OD.... But anyway nice car....

[Mater]

od is over rated the 97 works just fine as a 3 speed lol i just get 19mpg instead of 25mpg

welcome

just changing the filter and trans fluid should not hurt any thing

[w98seeng]

"If it ain't broke don't fix it"

Exactly. Don't worry about any gaskets until they are needed. When I get a new used car there are always things I do...

1) A good tune-up
Oil/filter change
Spark plugs (I always use the plugs the manufacturer specifies. I have tried fancy plugs without any benefits)
Wires (if necessary)
Air filter
Fuel filter

Tranny fluid/filter change

I don't use additives for fuel or tranny, I don't believe they help.

Ian

[Impala131]

Thanks for all the advice, guys. Good to know the head gaskets shouldn't be an issue. But I see there are different opinions on whether or not to do the LIM gaskets. I'll have to think it over, I guess.

As for the transmission, a buddy of mine is in an auto program at FSU, and he seems to think Dexron VI is worth the extra money over Dexron IV. Would you guys agree with that? Do both types of fluid mix? (I will probably just do a pan drop and change the filter and replace whatever fluid comes out.) I just did the same thing with my Lesabre's L36 but I used generic fluid since I'm real nice to the car anyway.