Normal Oil Consumption? 09 Yukon Denali 6.2

jjdurrant · January 7, 2021

I know this topic is beat to death at times but wanted to share my current situation.

2009 Yukon Denali 6.2 FlexFuel with 147k (no AFM for this year)

I bought it back in August with 141k miles. It is a spare vehicle. I did oil change with Amsoil Signature at that time. In October at about 143k it was a 1qt low. I randomly checked the oil today and it did not even register on the stick and took 2qts.. yikes. So it seems I am averaging 1qt about every 1500-2000 miles. Does this seem excessive?

Also to note, the oil and antifreeze appear clean. And no leaks present at valve covers or underneath. However, I do periodically see a little blue smoke and sweet smell on initial startup. it is not very often though and never notice when driving.

Thoughts? My initial thinking is maybe valve stem\guide seals?

CamGTP · January 7, 2021

Yeah that is a little much but I still think GM says that ~1qt per 1,000 miles is still fine (which it really isn't).

It's possible that it's the valve stem seals or maybe even the driver side valve cover. I thought there was an updated cover that came out after like 2010 to help with burning oil with the PCV.

Edited January 7, 2021 by CamGTP

Ian Mills · January 7, 2021

12 minutes ago, CamGTP said:

I thought there was an updated cover that came out after like 2010 to help with burning oil with the PCV

There was. The updated Dorman brand part is 264-969.

mjm-1957 · January 7, 2021

More than likely with that mileage a good decarbonization with top engine cleaner may help to free up the piston rings and may help to lower your oil consumption but it is within GM guidelines.We are told that 1qt per 1000 miles is acceptable as stated above but I agree that is excessive. Just because I work there doesn't mean I agree with that.guideline.

newdude · January 7, 2021

Oil consumption per GM is no more than 1 quart every 2000 miles.

Not 1 quart per 1000 miles.

mjm-1957 · January 7, 2021

Of course you are correct, brain fade, sorry for the misinformation.

Grumpy Bear · January 8, 2021

From an engineering standpoint the name on the valve cover makes no difference. It is considered 'normal' when the oil used is about 0.03% with a maximum of 0.05% of the fuel used. Mineral oil. (For automobile ICE gasoline motors)

One source of this type of information is: (MIT, CSM, SAE are others)

https://cdn2.ms-motorservice.com/fileadmin/media/MAM/PDF_Assets/Oil-consumption-and-oil-loss_51747.pdf

Say you have a 5.3 with an EPA average 18 mpg and drive 5K between oil changes. You will consume 277.78 gallons or 1111.11 quarts. At .03% 1/3 of a quart normal with a maximum of 1/2 quart per 5,000 miles.

Say your towing heavy and averaged 8 mpg. About 1.25 quarts per 5K mile OCI would be maximum and 3/4 quart 'normal'.

Of course there are motors that do better. Sometimes fuel dilution will add back level. 2% in a 6 quart system is almost 4 ounces nearly replacing good normal usage making it appear as the motor uses no oil.

Sometimes it's just a great motor seal and you get allot better. Some long OCI users claim 20K with under a quart. :dunno:

You cut usage another 30 to 50% with a oil with a NOACK under 6%. An easy foot helps. Note that usage is tied to fuel usage and by extension average horsepower, torque, BMEP, MAP, RPM etc.

GM's claim of a quart in 2,000 in such a motor is 10X higher than acceptable engineering upper limits.

The public is ignorant and they know it and take advantage of that fact.

Sharpz · January 8, 2021

Just to put this out there, if my truck was down 2 quarts of oil in between oil changes of 3k miles, I would be in a panic. I did notice my truck was down 1/2 to 3/4 qts at around 3k. I didnt see any oil in my drive way but, when I changed out my oil pressure sensor there was a bunch of oil on the back side of the engine. Since changing that out I cant see much oil consumption at all. It wont be all of your issue, but its something you should check on. Also my truck doesnt have a filter under that pressure sensor, but yours might.

I spray really good under my truck at each car wash, also use the automatic ones so oil probably was being washed away, and just not enough to make it to my drive way. or landed on the skid plate concealing it.

jjdurrant · January 8, 2021

Thanks all.. I will keep an eye on it. I just had the motor mounts done and the mechanic said he did not notice any leakage anywhere so that is good. I am a bit surprised there would be no leaks though given the consumption and clean oil and antifreeze overall. I wonder if it's just crappy valve cover PCV baffle design that allows excessive amounts of oil into the intake.

I suppose as long as I keep oil it in it should just push on without issue?

Ian Mills · January 9, 2021

A good top end clean and a new valve cover is a super easy fix and less than 100 bucks. If you haven't replaced the PCV lately I would do that. $100 is a good amount of oil but at the rate you're burning... lol

Edited January 9, 2021 by Ian Mills

jjdurrant · January 9, 2021

So should I just do the drivers side valve cover then? Also, is the PCV built into the new cover because when I search the auto parts stores for just PCV valve I get no results. Thx!

Edited January 9, 2021 by jjdurrant