Just got a 98 GTP, and...

[blazindave]

I love it!

although I've got one concern:

I have noticed that motor oil seems to be disappearing too quickly... it was completely dry underneath when I bought it, and the oil was clean and full, as though it had just had an oil change (as the previous owner said). Now, after a week, I have already had the "Low Oil Level" light come on and I had to put a quart in (which put it barely in the crosshatches)... I live in an apartment complex where I park in different places all the time, but I have been trying to look as I pull out of a spot if there are any fresh oil stains, and have not been able to find any... And it still looks dry, both from the top and from what I can see underneath... So I don't feel like it is really leaking oil (I really need to get up under it and look a little better, but)... could there be another problem I am missing? I hope this is something simple... hoping I didn't just buy a car that is gonna cost a whole bunch more money so soon

Other than that, I am lovin it - quick and fun... I'll just be glad when I move in to my new place very very close to work - the mileage is not so hot, gonna try to look into improving that...

It is a 98 GTP with Series II 3800 S/C, motor and tranny have 21500 miles

btw, I think this forum is very useful and plan on frequenting



edit to add: also, what kind of bulb for the fog lights? I could not find anywhere in the Owner's Manual the fog light bulb specification - found every other light on the car, just not the fogs... thanks again!

[GTP Dad]

Place cardboard under your car the next time you park it, if it is leaking then you should be able to find it readily. There are a couple of areas to look. First, check to make sure the oil filter is properly sealed. Second, make sure that the oil pressure sending unit is not leaking. It is located just above the oil filter. Finally, crawl under the vehicle and look at the oil pan area. These cars do have problems with oil pan gaskets. Unfortunately, if the pan is leaking then you will have to raise the engine to get to it to replace the gasket. If you can find out where the leak is coming from then post again and someone will give you additional help with the problem. Sorry I don't have the fog lamp number.

[BNaylor]

Got you covered GTP Dad. Fog lamp bulb # is 880.




Thrasher CAI, DHP v1.0 PCM, SLP Headers,
3.25 SC pulley, CAIT GMAF, 2.5 DP/Hi-Flow CAT,
u-bend delete, 160 TS, ZZP Stage 1 72mm TB,
TB spacer, MSD 8.5mm wires, Autolite 103,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials
1/4 ET: 13.210 sec. @ 104.490 mph
0 - 60 ft: 1.945 sec.

[regalfriend]

i know that sometimes that oil leaks can happen when driving the car, while the oil pressure is higher, and stop leaking while the car is idleing or stopped. Like GTPDAD said place cardboard under the motor and let the car run and even hit the gas to bring the rpm's up to about 2500 or so. If you lost a quart in a week and there is a leak you will definitly see it....another thing to consider is that you may be burning oil...do you see any white smoke coming from the exhaust?...as for milage my 1997 regal gs was rated 17 mpg/local and 28 mpg hwy...at best if i drive this car like a grandma i get about 14 or 15 mpg local and 25/26 hwy...only thing you can do is to make sure you are always completely tuned up and lay off the gas....but...laying off the gas is no fun, right?

[blazindave]

hey thanks so much for the quick responses! I am gonna do the cardboard thing this week and I will post the results...

thanks for the fog # too

[blazindave]

Okay, so I've been really busy and hadn't had a chance to really check it out lately, but last night I left cardboard under it overnight. This morning, clean as it was when I left it. So... A little while ago, I put the cardboard under it, started it, and gave it a little rev. Let it run for a little while, and still no oil on the cardboard. From what I can see without getting all the way underneath, it is completely dry underneath.

So I believe it has to be burning oil. Also, I noticed that the exhaust pipes (a little more on the left one) have a slight coating of black residue - it is dry, not wet) on them... It is not really a lot, but I guess it supports my theory of oil burn.

Any ideas on what might be causing it, and how to fix the problem?

[GTP Dad]

If you were burning as much oil as you state the blue smoke would be rolling out the tailpipe. There has to be a leak somewhere that is causing your problem. Check the area around the valve covers. The gaskets will leak and cause oil to run on the exhaust manifolds. It usually burns off right away so you may not see any oil. Just a thought.

[blazindave]

good idea, thanks - I'll check it out this weekend

[GTPgirl]

Originally Posted by regalfriend

as for milage my 1997 regal gs was rated 17 mpg/local and 28 mpg hwy...at best if i drive this car like a grandma i get about 14 or 15 mpg local and 25/26 hwy...only thing you can do is to make sure you are always completely tuned up and lay off the gas....but...laying off the gas is no fun, right?

Hmm. I get 22mpg out of my '99 GTP and that's with me driving like a maniac. If I toned it down, I'd probably get 23 or possibly 24 (which would be good considering current gas prices.)

The GTP's require at least 91 octane gas, and I run 93. I've found I actually get better mileage out of the higher octane gas than I do the regular. As for getting better mileage otherwise, a complete tune up, with new plugs/plug wires and air filter will help, and driving with the Performance Shift off will help a little (Although, I rarely drive without mine). And use the cruise control. All in all, 22mpg isn't bad for a supercharged V6 like these.

[blazindave]

that was another question I thought of - how does the performance shift affect economy? Thinking about it, it makes sense to me that since the tranny is shifting at a lower engine speed, it would help economy b/c the engine wouldn't have to rev up as much to shift gears, but it also helps you get up and going faster so it would hinder economy... ideas, thoughts, suggestions?

I have been doing most of my driving without it, becuase it encourages me to drive slower and more grandma like and I just figured it would drain my economy, but maybe not so much? Does it wear on the tranny any more than regular?

I've been getting around 19-19.5 mpg (according to the dash mpg thing - how accurate is that, and how does it calculate, from the fuel gauge?)... Mostly short trips <5 miles per...

real busy this weekend and didn't get to look at anything, will try this week and update.


edited to add: What is the best service manual for the GTP? Haynes? Chilton?
Also: I have an aftermarket stereo (Kenwood eXcelon) and the steering wheel controls are hooked into it - only problem is that since I got the car, they are working less and less... sometimes they work, sometimes they don't - when I first got it, they worked everytime, now not so much - how hard is it to get at them and check the connections? I don't know much about airbag stuff, and would not want to mess that up!

[blazindave]

Update:

Replaced the PCV and air filter. Also put in some STP Oil Additive when I added oil (I added straight 40 weight). I just used the additive not expecting much, but it was cheap, so I figured what the heck - man that stuff was like honey!

Also got a full tank of gas ($42!) and put in some STP fuel system cleaner additive.

Looked underneath a little better and it still looked completely dry. It looked like it could have been slightly wet around either the drain plug or the pan gasket, but I felt it with my finger, and it was dry. I also did the cardboard thing and revved it up for a little longer this time - still no oil on the cardboard.

Looked closely around the engine both running and off, and could not find any evidence of a leak of any sort.

So after I got the gas and fuel additive in there, I reset the avg mileage thing on the info center. Now it shows only about 14 mpg, where it used to show about 19 - is this just because it will take more time to properly adjust (I hope so!)? I've only driven it about 15 miles or less since...

One other thing: While I had the cover off the engine after I replaced the PCV, I cranked it and it sounded like there was a vacuum line off or something, kind of a constant hissing - I looked at all the vacuum lines I could see and they all looked good - although I did see what looked like a nipple for a vacuum line connection that had no line connected to it, only a piece of foam covering it up with a clip sort-of thing around the nipple. It did not have any suction that I could feel with my finger, and the sound didn't change when I covered/uncovered it, so I don't think that's the source of the noise. Is this noise just normal?

[StevePT]

You added straight 40wt oil? Why?

I wouldn't run heavier oil than 10w30 in a daily driver.

Not to insult you, but are you making sure you check the level on completely flat ground? Also, when do you check it? Is the engine cold, warm, just after a long drive?

Your mileage reader essentially turns into instant MPG until you drive enough for it to get a good average reading.

Not sure about the vacuum leak. I don't have that motor.

[ChrisB-98GrandPrix]

Originally Posted by blazindave

I love it!

although I've got one concern:

I have noticed that motor oil seems to be disappearing too quickly... it was completely dry underneath when I bought it, and the oil was clean and full, as though it had just had an oil change (as the previous owner said). Now, after a week, I have already had the "Low Oil Level" light come on and I had to put a quart in (which put it barely in the crosshatches)... I live in an apartment complex where I park in different places all the time, but I have been trying to look as I pull out of a spot if there are any fresh oil stains, and have not been able to find any... And it still looks dry, both from the top and from what I can see underneath... So I don't feel like it is really leaking oil (I really need to get up under it and look a little better, but)... could there be another problem I am missing? I hope this is something simple... hoping I didn't just buy a car that is gonna cost a whole bunch more money so soon

Question - has this only happend once? Have you only added the oil the first time or does it continue to need oil added? The reason I ask is if it was only the first time, the previous owner may have changed the oil filter and didn't prime it or run the car to circulate the oil. If he only added enough to make it show "full" on the dipstick, then it would be low after running it.

Just a thought.

[blazindave]

thanks for the tip, but yes it happens continuously...

I am checking it on level ground, usually I check it while it is still warm, after the "Low Oil Level" light comes on - then I add a quart.

I put the 40 wt in because I figured with a little thicker oil, it might keep it from burning as quickly - not a good idea?

and it doesn't really feel like it had a vacuum leak, just the sound had me wondering

had to drive about 30 miles or so this afternoon, pretty much all highway, and it started to level off around 18-19 mpg, which makes me feel a little better, but still - 19 mpg hwy and 13-14 non is not that good - just sounds like most people are getting a little better than that...

[BNaylor]

Originally Posted by blazindave

thanks for the tip, but yes it happens continuously...

I am checking it on level ground, usually I check it while it is still warm, after the "Low Oil Level" light comes on - then I add a quart.

I put the 40 wt in because I figured with a little thicker oil, it might keep it from burning as quickly - not a good idea?

and it doesn't really feel like it had a vacuum leak, just the sound had me wondering

had to drive about 30 miles or so this afternoon, pretty much all highway, and it started to level off around 18-19 mpg, which makes me feel a little better, but still - 19 mpg hwy and 13-14 non is not that good - just sounds like most people are getting a little better than that...

Since you're running higher viscosity oil check your oil consumption again. One quart in week is not good. Like the others suggested it has to be being burned off someplace. Have you taken a reading of your sparks plugs? If its being burned off in combustion it should show up on the spark plugs.

The only other thing I can suggest for now is run a compression test on each cylinder.




Thrasher CAI, DHP v1.0 PCM, SLP Headers,
3.25 SC pulley, CAIT GMAF, 2.5 DP/Hi-Flow CAT,
u-bend delete, 160 TS, ZZP Stage 1 72mm TB,
TB spacer, MSD 8.5mm wires, Autolite 103,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials
1/4 ET: 13.210 sec. @ 104.490 mph
0 - 60 ft: 1.945 sec.