I have an 09 GMC Sierra with 95,000 miles on it (bought it new Jan 1, 2010). It has the 5.3 L V8 with Active Fuel Mgmt (all 4 AFM lifters have been replaced due to the fact that they collapsed about 20k miles ago) and has been a solid truck except for the fact that I have an oil consumption issue that I feel is not normal. When I first bought the truck, I used about 1 quart over 9,000 miles (truck as oil life monitor – when it says ‘change oil’, then I change the oil). Now it is using quart ever 3,000 miles. I do not have any oil on the ground so I know I am not leaking. I do not have smoke from the motor so I am not burning it and my compression is almost perfect across all 8 cylinders. I take it to the dealer for all the work and they tell me that ‘1 quart per 2,000 miles is considered normal by GMC’ which seems ridiculous to me. I have not modified my driving style (mostly hwy, about 70-80 mph, 80 miles per day), so why am I now using so much oil? My oil pressure is the following: (1) initial start up: about 38 lbs on the gauge when I drive and idles about 20 lbs, (2) warmed up: about 25 lbs on the gauge and idles about 18 lbs. Are my rings jacked or possibly the AFM lifters are letting stuff by? I am about ready to get rid of the truck…
The OLM has created problems because the oil change interval is too long and this leads to the creation of oil sludge or oil coking.
The lifters may have given up because of lack of oil due to sludging.
You state that the compression is perfect across all cylinders but that may mean nothing.
What would be more important to know is the actual number and whether both a dry and wet compression test was performed and the reason you don’t see smoke is because the converters are catching it.
The oil pressure sounds a bit low and the oil sludging i mentioned affects more than the rings and lifters; it also plays havoc with crankshaft bearings and crank journals.
hmmm…what would you recommend?
hmmm…what would you recommend?
- Change the oil at 5000 mile intervals
- Check the oil every 1000 miles or once a week. Add a quart of oil if necessary.
- Quit worrying and drive on. One quart per 3000 miles isn’t unusual.
Ok…anything I need to do to remove the sludge, if there is anything gunked up in there?
1qt per 3000 miles is normal, especially with a large engine.
Toyota considers 1qt per 600 miles the threshold for warranty purposes.
The catalytic converter can “digest” smoke from mild consumption.
Engines tend to consume more oil under constant high speed operation.
How many miles typically between oil changes?
I recommend you fuggedaboudit and drive on.
Usually what happens with oil sludging or coking in regards to oil consumption issues is that the oil control (wiper) rings seize in the piston ring lands, or grooves. About the only thing that can be done short of tearing into the engine is to try an additive such as Berryman B-12 or Seafoam in the engine oil and see what happens.
Without knowing the compression numbers it’s impossible to make much of a guess and it’s also possible to have great compression numbers and still have oil consumption issues due to the oil control rings being stuck.
GM has a service bulletin out about the OLM on this era of vehicle but it does not include the Sierra.
Unfortunately, it probably should and other than an additive it’s something you will have to live with.
All car manufacturers claim that a quart per X miles is normal but they have a vested interest in those kind of statements.
There are plenty people that wish they only used 1 qt/3000 miles!
Keep checking that oil level regularly
You are nowhere near the threshold to qualify for a replacement engine under warranty
IMO the oil pressure sounds like it’s within normal parameters
I just made the same comment in another posting, but try a different brand of oil. While using a quart in 2,000 miles is by no means excessive, try using a full-synthetic. My vehicles use a little oil with Mobil-1 on board, none at all with Amsoil. Both are excellent oils and I think your consumption would drop if you used ANY synthetic. Also, 9K miles is way too long between changes, as others have said, even with synthetic, unless you do purely highway runs all the time. I go with about 5K oil changes on my vehicles with synthetic oil, which equates to about 2-3 oil changes a year. Some would probably chastise me for pouring money down the drain, but I’d rather spend an extra $50 or so a year for the privilege of never worrying about my engine internals.
^
Maybe yes, maybe no, oblivion!
With a friend’s Rav-4, I always have to add 1/2 qt. every 1,000 miles. As an experiment, I tried using a full synthetic (Castrol, IIRC), in order to see if it would reduce his oil consumption.
It turned out to be a somewhat expensive experiment, as the rate of oil consumption was exactly the same with that synthetic as it was with his usual Mobil “dino” 5w-20 oil.
@VDCdriver: I can only report on my own experiences. My 2006 300C uses about a quart in 5K on Mobil-1, about ½ quart on Valvoline Synpower, and for the last 2 oil changes on Amsoil, has not apparently used any oil. The recommended 5W-20 has been used with all oil changes. I have run Mobil-1, Valvoline, and Amsoil in this car for at least 2 oil changes each, and for both summer and winter driving, with the same driving habits. (spirited)
As the saying goes though: “Your mileage may vary.”
The GM service bulletin for the OLM is limited to the V6 engine of that era. The OP’s car is the V8, which may explain why it’s not included.