Oil and it's disappearing act

[dbuckley510]

I have a 2008 GMC Sierra 1500 Crew Cab V8. I took the vehicle in at 100,005 miles for an issue with white smoke occasionally coming out of the exhaust on a cold start. I was told of course warranty is past and they replaced what parts they could that were "covered" but I'm still losing oil. No white smoke, but oil is dropping fast. No oil on the ground ever either, so it has to be burning up somehow or I'm still losing it in the engine. I have to take back to GMC tomorrow and just wanted to check if anyone has ideas before I get charged a ton. Other than this recent event, love the truck! Now it's up to GMC on what they will cover cost wise and that will determine if I'll become a customer for life. Thanks!

 

[Bill325]

You might check and see if there have been any factory service bulletins issued on your year truck that might be connected to your oil loss. I have a subscription for my two vehicles with an online data service to identify service bulletins and recalls. That information may also be available for free , somewhere. If you're seeing an oil loss on the dipstick , the oil is either leaking onto the ground, burning in the engine, or getting into the cooling system.
Burning a quart of oil every one thousand miles is considered reasonable by some manufacturers . Changing to a heavier weight oil will usually decrease oil consumption in well worn engines. Do a thorough cleaning and inspection of the the PCV system . On a high mileage engine, there's almost always some part of the PCV system that's clogged , disconnected, or otherwise malfunctioning.
The PCV inlet at the base of the fuel injection body on my truck was so clogged with rock hard carbon deposits that I had to remove the throttle body and chip the carbon out piece by piece. Make sure you fully understand how the entire PCV system works by referring to a manual. Good luck !

 

[mdwebb88]

I had the same issue with my 2007 Sierra. Man, i was getting so frustrated because i was constantly adding a quart of oil every 1000 miles. I bought my truck used with 85k on the engine and for the first 5-10k i didnt have an issue with oil consumption. Once i started to get around 100k miles, i began to have an issue with the oil consumption.

My truck was still under the warranty that i purchased so i was able to have some work done to it. The first thing they did was replace all seals and gaskets and cleaned out the ports. That had no effect on the consumption issue, so i went back. They told me that what they did should have fixed it but they will do some research and see if there are any other options besides putting a brand new motor in.

Well, there was one option, and that was replacing all the pistons. Ever since they did that, i have not had a consumption issue. (ive put about 15k on the motor since they replaced the pistons) Maybe, if you have not had this fixed yet, you could suggest this to the mechanics.

Hope this helps!