hi first post on here! i have a 2005 pontiac grand prix with the 3.8 current milage is 25500. have owned since new and from new it has burned up 3/4 of a quart in 6000 miles . i have been changing the oil at 40% on the olm which usally is around 6k on the oil.was using mobil 1 then the last change i went to amsoil asm 5-30 and the burning is still there. so the next change will be sso 0-30. is this a acceptable amount to burn or is it to much? the car sees very frequent short trips of 2 to 10 miles and ocassinle long trips. i just need to now how much oil this motor should use if any.
3.8 in pontiac oil usage
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That really isn't a large amount of consumption. You can, however, make a few quick checks for other known consumption routes. Pull the ducting where your mass air flow sensor is and see if there is oil in the ductwork. Also check the PCV valve and it's routing hose to see if there is oil there. The 2000-2004 grand prix's that I used to work on would start consumption via the intake route after about 55k miles. If you don't see oil in these parts the remote oil cooler lines also develop slow leaks over time. General Motors should have the environmental police after them becasue every single cooler line on their S-series pickups would leak profusely near the crimp fittings after about 60k miles. They probably have put more used crank oil into the environment then all the Bubbas who think used crank oil is a substitute for round-up.
Oh yeah and
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While directed at the supercharged Grand Prixs mostly, some have suggested a catch can in the PCV line.
My 4th Grand Prix is still oil tight as were the previous 3.
Some 3.8 developed a slow leak around the valve covers; check for seepage.
My 2¢
My 4th Grand Prix is still oil tight as were the previous 3.
Some 3.8 developed a slow leak around the valve covers; check for seepage.
My 2¢
That's not alot of consumption. If it bothers you, try using a robust oil like Penz High Mileage 10w30 (even tho you only have 26k on the car). See how that does. GM was specing 10w30 a couple years ago.
I had a 1998 olds intrigue for 5 years that I bought brand new, and used castrol 10w30 exclusively at 4-5k mile oil changes and it used 3/4 to 1 qt per oil change.I traded it for my wifes current 2002 Trailblazer just because the family got a little bigger.
I have a 2000 3.8L SC and the consumption you have is normal, really really not at all excessive. Mine will use more at extended 70 mph trips, in the 1 ounce per 200 mile range but around town in the 1 ounce per 250-300 mile range.
excessive is 1 quart in 2500 miles in my opinion. a quart in 7000-7500 is absolutely great on any engine.
I was getting some clattter ( 65,000 miles on mine) and started mixing Amsoil 10W40 with their Series 3000 5W30 50-50 ratio and it has removed the valvetrain noise and runs fine. I consistently get 30 mpg highway and 20-23 around town.
excessive is 1 quart in 2500 miles in my opinion. a quart in 7000-7500 is absolutely great on any engine.
I was getting some clattter ( 65,000 miles on mine) and started mixing Amsoil 10W40 with their Series 3000 5W30 50-50 ratio and it has removed the valvetrain noise and runs fine. I consistently get 30 mpg highway and 20-23 around town.
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well the sso showed up this evening so i changed the oil out replaced the filter with a eao29 and added so P.I. improver to the gas. now we"ll see what does now . no oil in the maf sensor ducting. and that oil change only had 4000 on it not 6000 like i thought .so is 3/4 of a quart bad in 4000 miles?
IIRC, the 97-2003 Grand Prix, indeed all GM 3.8s of those years specked 10w30.
High mileage oils tend to be on the thick side of 30 weight.
High mileage oils tend to be on the thick side of 30 weight.
By the way there was a recall a couple of months ago on the 3.8Ls to replace the front valve cover gasket due to seepage and possibly causing a fire. I believe it was only on the SC engines.
Even 24 ounces in 4000 miles is not too bad, but I would start to keep track of it with attention to type of driving and relationship to the consumption. These 3.8L are pretty much workhorses and one of the best GM has ever built, the reason they are still around in the showrooms
Even 24 ounces in 4000 miles is not too bad, but I would start to keep track of it with attention to type of driving and relationship to the consumption. These 3.8L are pretty much workhorses and one of the best GM has ever built, the reason they are still around in the showrooms
I had this engine in a 1994 Lumina APV, developed consumption via a leaking cooler line, got that fixed and consumption went to less than a quart in 6000 miles. I might still be driving it if I hadn't hit a deer at 179,000 miles.
I'd say your engine and oil usage are fine, and you have nothing to worry about. Every owners manual I ever looked at says its OK to use some oil. As far as changing to a 0W-30, go for it, especially during the colder seasons.
Frank D
Frank D
Like the guys said, that consumption is not too bad. My 3.8 was in a '95 LeSabre and I got 300,000 km out of it. The first part of it's life was mostly Penzoil 5-W-30 dino at 5,000 km changes. The last 200,000 km saw a steady diet of GC (0-W-30)at 6 month OCI (12-14,000 km). My top-up volume during this time was about 1 liter, more or less and I could not find any leaks, hence I did not worry, just normal consumption. When I retired the car, the engine was still going strong. However the body rusted out thanks to the salt on the roads in winter 
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