2007 Silverado 1500 New Body Oil Consumption

[skipcfd]

I have been using a lot of oil between oil changes and usually adding more every 2k miles. I had taken my truck to a mechanic and he said the PCV valve cover was an issue with the truck so I replaced that. After that, I was still using a lot of oil, with no drips noticeable until I changed the spark plugs and noted on the right side of the motor, there was oil at the back of the valve cover. So, I replaced the gasket, and went to a conventional oil instead of a high mileage. I did my routine oil change, again, and now after 2k put on it after the oil change, I had to add 2 quarts of oil. There is no visible drips or leaks that I can find. Any ideas????

[Supreme Pizza]

No signs of oil on the plugs? No drips? It's gotta be burning it, which will mess up the cats. Anyone else have any ideas? 

[dsr611]

Grab you a bite to eat and something cold to drink, sit down and read for a while

http://www.gm-trucks.com/forums/topic/127812-is-your-gmt-900-truck-or-suv-using-oil/

 

[diyer2]

From your info, and now after 2k put on it after the oil change, I had to add 2 quarts of oil

You didn't let it get 2 quarts low did you?

A quart of oil every 1 k miles?

Rings and valve guides.

 

[e.p.]

Check number 1 and 7 plugs. I bet they are oil fouled.

[Supreme Pizza]

No idea if this is relevant to your vehicle, but I have seen certain engines that need a will use oil with the OEM PCV valve. You may be able to resolve the issue by getting a differently designed one. Some people solve this issue by installing a simple catch-can on the breather tube. I would try to build/buy one that will self drain back into the motor when you shut the rig off. I had the same setup on a go-cart once, and it worked great. Much less oil burning. 

[Mike GMC]

Never put the contents of a catch can back into the oil!  There will be water, oil, fuell, acids and other contaminants in it that you don't want back in the pan.

 

Unfortunately for the op, it sounds like rebuild time.

[Supreme Pizza]

My go cart was farting out about 1 quart of oil into the catch can every half hour of driving, so having it drain back into the motor was a necessity. On a regular vehicle, I would throw the oil away - unless it was a huge volume of it coming out of the motor. 

 

What about running a leak down test? Or pulling the exhaust manifolds to see of the valve stems are soaked with oil? Could be something as simple as valve guide seals. If so, this might be worth a shot before you tear the motor apart: 

 

 

 

 

 

 

[Logan Lanfear]

Run a compression check.  That should give you an idea of how worn it is.  Whats your exhaust smell like?  Id bet it smells like burnt oil.  

[newdude]

Pistons and rings. 

[MaverickZ71]

There is a reason the owner’s manual says to check the oil every time you get fuel—because chances are, you may need to add oil. 

[skipcfd]

UPDATE. I have done all the updates that GM has put in the bulletin for the truck. When, my mechanic removed the oil pan, the deflector was already in place, and done by someone prior to me owning it. The pcv valve is new. The valve cover gasket on the right side had been changed also. My mechanic said that he didn't think a compression test was needed because the truck doesn't appear to be running rough.

 

Any ideas?