Question for Truck/Car Mechanics on 6.2 GMC

[CaymasRodney]

My 2019 GMC Denali with 6.2 started using oil two oil changes ago, last oil change I had to add two quarts. My local dealer is doing an oil testing on this oil change, took it in today have them check at 1000 miles it was a half quart low. That would be about 2 1/2 quarts between oil changes the way I figure it. It went for 50,000 miles not using one quart. Got warranty until May 31 through GM extended warranty. I have ran Chev/GMC for years and years, never had this type problem before even when I was running a Duramax.

Any thoughts appreciated ??

[Champ 2001]

What type oil and weight are you using?

[1Holeshot]

Common with the active fuel management engines. Same thing happened to my GMC Sierra 5.3 engine.

All eight pistons and rings had to be replaced.

As as soon as I got it back from dealer traded for a Toyota.

[CaymasRodney]

[IMG][/IMG]

[CaymasRodney]

Common with the active fuel management engines. Same thing happened to my GMC Sierra 5.3 engine.

All eight pistons and rings had to be replaced.

As as soon as I got it back from dealer traded for a Toyota.

Trying to convince my wife that is the right thing to do BUT

[Champ 2001]

I read that those engines that were using oil like yours were going to 5w-20 weight oil. Also a few customers found pistons and walls scored and the dealers replaced their motors. Good luck with getting yours resolved.

[mactlman]

my shops usually replace the pistons to fix this. valve cover sometimes if not too high of consumption

[yatesville88fan]

I believe I would trade this truck.

[Woody b]

There's no magic fix that I know of. Snake oil, is simply.....snake oil and isn't going to repair anything. GM considers up to 1 quart per 2000 miles as "acceptable". Some manufacturers consider up to 1 quart every 1000 miles as acceptable, so it's not just a GM problem. Many things going on with modern engines can cause oil consumption, most of which are tied to fuel economy. Your engine varies the valve timing to limit power, while keeping the throttle open as far as possible. This helps fuel economy by reducing pumping losses. This also hinders the PCV system from working properly due to low manifold vacuum. They also use very low tension rings, to help with friction. This is to help with fuel economy also. The low ring tension, especially after an engine has a few miles on sometimes have problems controlling oil.

Hopefully they'll repair in under warranty. GM requires an oil consumption test. When I worked at a GM dealer if an engine was borderline on excessive consumption I'd "fudge" the test a bit so it would qualify for repair.

Good luck.

[shapfromla]

My experience with 3 GM V8 engines that were equipped with the AFM V8/V4 switch has been that they will use some oil. Each time I have bought an AFM disabler from Range to keep them in V8 mode all the time and the oil consumption pretty much stopped completely. May not work every time but I like having all 8 cylinders all of the time and it has been a cost effective upgrade for my vehicles.

FYI, I am not a mechanic in any way and my experiences may just be coincidence. I do my own oil changes and that is about the extent of my mechanical abilities.