So I purchased my 03 STR about 2 months ago. The previous owner had the car since 40k miles ( now pushing 166k ) I also received all his maint. receipts upon his ownership which was a good chunk for owning the car that long. Runs, drives and sounds great and rides nice besides some front-end play which I cannot pin point.

I have noticed oil loss, sometimes a lot sometimes minimal. Sense ownership I am noticing more oil loss only when the car is driven harder than usual. Few' days ago I checked my spark plugs and they all had some oil on them, not a LOT but still not good. One spark plug had a lot of burnt and sludge looking oil, so I changed 6 of 8 ( 2 looked fine ) with NGK plugs and also gave Lucas Full Synthetic Oil Additive a shot, $16.99 a quart which has good reviews. I used the the full quart along the oil I had in my car which has about 1500 miles on it ( not fresh motor oil but not too old ) checked my dip stick after car ran a few minutes and my oil level was close to the full " o " mark.

Yesterday I drove the car pretty hard a couple times, nothing too bad. I do notice when I drive the car harder than usual I have a funny smell come through the cabin that lasts about a minute.
Check my oil today after letting the car run about 3 minutes to find the oil level on my dipstick just a little above minimum level.

I have NO oil leaks, example being no drips in my garage floor or in the belly pan. With my old plugs having a little oil on them I am thinking my intake gasket is due for a change but no-way in hell should it be causing my excessive oil loss problem, Right?

I have read and been told these engines do burn a little oil being Supercharged, Oddly I have owned 4 Grand Prix GTP's (Supercharged 3.8 V6) and never noticed oil loss/consumption with them at all.

So to wrap this thread up - What are my options here? My car doesn't overheat, tick or knock. Am I screwed? Is putting fresh motor oil in my car every week doing my motor harm? My next option is doing a compression/ leak down test but if I find I have bad compression in a cylinder is there anything I can do? Does this sound to you like I am having Piston Ring problems?

For you STR owners - Note my car has 166k miles and no service lights. ( Scanned regularly )

Any other high mileage STR owners noticing these problems? Maybe its a higher mileage kind of thing.

Thanks in advance,
Corey

 

Well if it's not leaking it's burning away, do you see any smoke from exhaust on hard acceleration?

 

Well the STR is not reported to use much if any oil?

My 2005 STR at 93K might use a quart every 5K-7K miles depending on how hard it's driven.
But I think you have about the most miles I have seen on any STR so maybe just the high mileage?? Before intake gaskets I would suspect and maybe even change the valve stem seals. Age and heat harden them and on other high mileage cars I have replaced them with the heads still on the motor for a fairly cheap price.

Now I am not sure I would try that with a 32V DOHC engine though!!
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I noticed the excessive oil loss as well. I used to get a small puff at startup, but ever since I went to the catch can, that has stopped. I do tend to get quite a bit of oil in the catch can, so the only thing I can surmise is that the PCV system circulates a lot of oil. When I replaced my hose beneath the s/c there was vast oil deposits on everything it seemed like (tb, elbow, s/c), and that is why I went with the catch can. Maybe due to the high psi from the s/c it creates high pressure in the system?

 

You could start with the cheapest option of cleaning the full and part load breathers. Lots of posts about cleaning the part load breather orifice can be found.

 

Oil on your plugs would indicate the seals around the tubes are leaking. Pull the valve covers and replace the seals; they are probably hard and cracked and leaking the oil into the plug tubes. Also, are you sure you aren't leaking oil onto the exhaust and its burning off before it hits the ground? That could be your smell.

 

Well when the car is parked there is never a drip of oil anywhere on the ground so I highly doubt it. I noticed tonight when I got on it I could see smoke in my rear view from the headlights behind me shinning on it. It was a small cloud. Hmm