2012 Sierra 5.3 Using Oil

[ServiceGMC]

My 2012 Sierra 1500 5.3L V8 looks like it is using oil. I have not seen any evidence of an oil leak. The truck has 60,000 miles on it. I am using Castol Edge oil. After about 3500 miles, the oil level on the dip stick is down to the last "dot". I do not know how much oil that indicates was used but if I add about 1/4 quart, the oil level rises to just above the next dot (second from the last). I think the oil life indicator says about 45%.

Any insight, advice, or information on other/similar experiences would appreciated.

Thanks.

 

[Bill325]

If oil isn't leaking onto the engine , transmission, or ground, and there's no evidence of oil in the radiator fluid, then it must be burning the oil. It sounds like the engine may be burning 3/4 to one quart of oil every 3500 miles. That's not too bad , unless the problem started fairly suddenly . Vehicle manufacturers have been recommending low viscosity oils in recent years to obtain a slight increase in fuel economy , but the thin oil isn't necessarily good for your engine.
You might try moving to a higher viscosity oil if you're using 5W-30 , or 0W-30 . A 10W-30 is fine for most engines , winter or summer. 10W-40 might be necessary in hot weather. I've run 20W-50 oil in well worn engines to keep oil pressure up and oil usage down, but you shouldn't have much wear at only 60,000 miles. There might be a factory technical service bulletin on your engine on this subject if it's a widespread problem. Also, check your engine for problems such as a clogged PCV valve or defective breather hose,or cracked or loose vacuum lines, or signs of antifreeze getting into the oil . Make sure there are no diagnostic trouble codes showing up on a code reader.

 

[ServiceGMC]

Thanks for the reply and the information.
As far as I can tell, the oil is not leaking onto the ground and I have not noticed oil in the coolant or the transmission fluid but I think it would have to a LOT of oil in the coolant/transmission before I would notice it. I have not seen any evidence of antifreeze in the oil.
I can't say whether or not the problem started suddenly because I bought the truck used two years ago and it has been doing this since then. However, the first time I changed the oil, I notice some small drops of oil coming from the oil filter and I thought that was the problem. But since then there have been no oil leaks that I can see and it's still "using" oil.
You've given me a few things to check out (e.g., PCV, vacuum hoses, OBD codes). I will do that. Living in Texas, the summers get pretty hot. I might consider bumping up the oil viscosity from 5W-30 to 10W-30 for my next oil change, although the owner's manual specifically says, "Do not use other viscosity grade oils such as 10W-30 ...". I have a feeling it would be OK.
Again, thank for the advice. Let me know if you think of anything else.

 

[ServiceGMC]

More information ...
There is an earlier post on this topic at this link:
https://gmcowners.com/gmc-forum/showthread.php?t=22358

In page 2 of that post, there is something that looks like a ... service bulletin(?) that has this at the beginning of it:

# 01-06-01-011I: Information on Engine Oil Consumption Guidelines - (Oct 27, 2015)

In that bulletin it says:

Oil Consumption

The accepted rate of oil consumption for engines used in the vehicles referenced is 0.946 liter (1 qt) in 3200 km (2000mi).

A link to what I think is the actual bulletin is here:
http://gm.oemdtc.com/698