petsur

Folks I'm at a loss and I'm looking for suggestions. Bottom line, my car used/lost 2.5 quarts of oil over the course of about 2000 miles. Below are the sequence of events (car was always 175F+ on a level surface when checking with the engine running):
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1. When I purchased the car new, I had a 2 day drive home over about 600 miles. I stayed off the interstate and drove two lane highways for the express reason of seating the piston rings. I'd take the engine up to about 2000 RPM then squeeze the throttle on building pressure going from about 40 MPH to about 110 MPH over and over, for 2 days. The car ran great.
2. With 1500 miles on the car I changed the oil. Chevy filter and Mobil 1 purchased from the Chevy dealer. I'm very **** when it comes to cleanliness. The drain plug and filter were very clean putting back together and I always run my bare clean finger over the surfaces checking for ANY fine grit or dirt after cleaning. The O rings on the plug were clean and perfect. I filled the car with 7 quarts then ran the car to check the level. I added up 7.5 quarts, rechecked and ultimately it took the full 8 quarts to get to the top mark.
3. About 1200 miles later I had found the oil level very low. Almost not showing on the dip stick at all. I went to the dealer and they offered to have the car towed in, or to fill the oil at home and bring it. I purchased two quarts at the dealer and took it home. It took 1.5 quarts to fill it. I left the car parked in the garage all weekend with the oil up to the full mark on the dipstick.
4. I brought the car to the dealer Monday morning about 9 AM fully warmed up. The mechanic took the car back after 15 minutes and checked it out. It was placed on the rack and there were no leaks. He told me he added a little more oil, but to go ahead and drive it and we would begin an oil consumption test. At this point, both the mechanic and I were sure the oil was full, to the top mark on the stick.
5. I left the dealership and that evening, drove up to the mountains and back, 130 miles. Returning home later that same day the oil was down to the lower mark on the dipstick, 1 quart low after driving 130 miles.
6. The next morning I drove it to the dealer and the service writer verified it was a quart low when I pulled in. I verified it was a quart low, and the dealer verified it was a quart low after both of us verified it was full the day prior.
7. The mechanic took the car back in and performed an oil change. He said the O rings on the plug were fine.
8. I have put about 1000 miles on the car since and it has not used a drop of oil yet.

I'm at a loss, I have never seen smoke, never smelled funny, the engine purrs, it's quiet and does not act like an oil burner. I had someone from another forum suggest the top O ring on the drain plug is used to keep the oil in the tank and prevents the oil from leaking from the tank back into the engine. That's the only plausible explanation I've hears yet as the dealer has not offered any explanation.

I was wanting to track the car but where I've had 2.5 quarts of oil go missing, I don't have confidence in this engine. Any ideas or suggestions on how to handle this with the dealer are appreciated.

Kracka

Engines will at times consume oil during break-in. Also, was the proper oil level check procedure followed? The dipstick is to be checked with the engine fully warmed up and running.

dohabandit

1 quart after 130 miles, wow.

Sounds like everyone understands HOW to read the oil level (warmed up AND *must* be running on level ground).
How could it burn that much oil and you not see it? A leak somewhere?

petsur

Right, but where? The engine is dry, which makes me think leaking past the O ring back into the engine is plausible.

It's strange that changing the oil made it stop. I mean going from 1 quart in 130 miles to zero oil consumption after the change.

waynger

Total guess here, some kind of return blockage say to the scavenge pump in the valley area? Piece of paper or silicone floating around that finally got picked up? On your next oil change cut open the filter, If it is ok for a couple thousand more miles "RUN IT"

petsur

I agree. I was hoping the dealer saved the first oil filter but he didn't.

petsur

Well, checked the oil yesterday and its down 1/2 quart. Have 900 miles on the car since oil change. It's funny, for 800 of those miles, the oil stayed full. The car has 4000 miles.

Racer X

Do you have a prankster at your house?

That is very strange. Did you drive the car differently in those 100 miles?

I am not saying it is aliens, but…….

petsur

Yes actually, I just drove it like a normal car. No hot rodding. Did about 50 interstate miles.

hunter105

You are checking the oil while the engine is running right???????

petsur

(car was always 175F+ on a level surface when checking with the engine running):

dohabandit

I just checked my oil at a fuel change. Engine warmed up, running, and on level ground.

I had the oil changed at 1750 miles. Oil was at the top of the hash marks on the stick after the oil change. I am at 3000 miles now and the oil level is 3/4 of the way down the hash marks. Only 1/4 of the marks are covered with oil. Not sure how much this equates too.
Is the range of hashmarks equivalent to 1qt of oil? If so, I am down 3/4 qts. Wonder if the dealer will top that off for me, or if I should just head to Advance/O'reilly's and pickup a couple quarts of Mobile-1 0W-40 ESP to have on hand?

My oil catch can was 1/2 full. (just dumped it) Consistency of the oil in the catch can is very light weight and smells like a mix of gas and oil.

Mikeki7

My dipstick readings are always inconsistent, could make me think I'm down 1/3rd a quart but I check it a few days later and it reads good. If you check the level at 175 and at 190 degrees would the reading not be different? You can add oil equivalent to what was in your catch can or just don't add anything as long as you are within the hashmarks. OP's situation is definitely weird, assuming the engine is not burning oil then something is preventing proper oil return to the tank and instead the oil is staying in the pan? In that case adding too much oil could be harmful. Hope you get it figured out quickly, please keep us updated.

MikeinAZ

Same here, I know its a heated debate but I (as do you and many others) see what gets trapped in there and it would otherwise be going thru and coating the intake track. I believe a catch can helps on these engines.

petsur

At 5000 miles now and has gone through 4 quarts. Still the level is just being monitored by the dealer and nothing has been done beyond the dealer checking/adding oil. I talked to Chevrolet yesterday and asked for an extended powertrain warranty. They said that is up to the dealer which really surprised me.