# ’05 Chevy Silverado – Where’s my oil going?



## Buck (May 11, 2011)

Quick search of the web and it appears this is not uncommon with the 5.3liter engine these days.  I’m talking 1qt every 1000 miles on an engine with 78k miles.  This trend started around 65k miles and seems to have leveled out.  There’s no oil spots underneath or smoke out the exhaust.  Anyone else having this problem and is there an additive or tricks available to possibly reduce the consumption?  I’m still using the 5w-30 the factory recommends.


----------



## fatboy84 (May 11, 2011)

Does your 5.3L have the Active Fuel Management System, that shuts down 4 cylinders at cruising speeds?

My 07 GMC Sierra Z71 went through 4 quarts in a 5K mile oil change.  

If so, take it to your dealer and have them clean the pistons and rings, and install the AFM shield.  Then hold your breath and pray that fixes it.  If not, they "should replace the pistons and rings", however after mine still used 1.5 quarts in under 2000 miles, GM decided to have the dealership replace the valve stem guide seals on mine.

When I called GM for an answer on how the valve stem guide seals would correct an issue that their service bulletin said was caused by carbon deposits on the pistons and rings, I ended up speaking to people in the Phillipines and Argentina (and these two guys were extremely arrogant).


I gave up and traded my 07 GMC Sierra Z71 due to this issue and the bad taste of a company that our tax dollars bailed out having their customer service reps in the Phillipines, and their "District Specialists" in Argentina.  I couldn't get anyone from the US on the phone other than my dealership.


----------



## fatboy84 (May 11, 2011)

Here is the service bulletin....  Of course the "District Specialist" from Argentina said it didn't actually mean anything that I had seen it and knew what they the cause was and waht the next steps should be, and we would all be too stupid to understand it since we are not Engineers. 




> TSB #10-06-01-008:
> Engine Oil Consumption on Aluminum Block Engines with Active Fuel Management (AFM) (Install AFM Oil Deflector and Clean Carbon from Cylinder) - (Aug 24, 2010)
> 
> 
> ...


----------



## rjcruiser (May 11, 2011)

Might try replacing the PCV valve.  To see if it is good, take it off and shake it around.  If it rattles, it is good.  If it doesn't, well, replace.


----------



## Buck (May 11, 2011)

Thanks Fatboy...  Stopped by the local dealer on the way home and they didn't mention the FMS as being the problem when they searched the VIN number.

However, they did tell me about this:  


> Excessive Oil Consumption And/Or Blue Exhaust Smoke
> 
> Support FSC and see no ads! - Click Here
> 
> ...



They also handed me a printout of a GM tech document released April 28th 2011, describing the same symptoms showing different solutions than the attachment above.

All seem to be related to the PCV valve.  This latest document describes a new and improved PCV valve which requires valve cover modifications to support the newly designed PCV valve.

Regardless, I have to get out my checkbook...


----------



## GoldDot40 (May 11, 2011)

rjcruiser said:


> Might try replacing the PCV valve.  To see if it is good, take it off and shake it around.  If it rattles, it is good.  If it doesn't, well, replace.


Not always. It can be clogged (or partially clogged) with carbon buildup, which will cause it to NOT rattle. However, if the spring inside is broken...which is VERY common....it will still rattle, but not function. The best practice is to just replace it once a year whether it needs it or not. They're fairly inexpensive.


Buck said:


> All seem to be related to the PCV valve.  This latest document describes a new and improved PCV valve which requires valve cover modifications to support the newly designed PCV valve.
> 
> Regardless, I have to get out my checkbook...


You're on the right path. The 'new' design PCV valve is a 'fixed orifice' piece. Basically it's the shell of a PCV valve with no moving parts. It simply has a tiny hole in the bottom that regulates the air flow and provides the correct circulation in the block. It's not an AC Delco part #, but a *GM* part # 12572717 (yes there's a difference). Not sure if it's available through a parts store, but your dealership parts counter should stock them. Write down the part # I posted above and take it with you.

I've remedied a many of oil consumption problems with newer GM trucks as well as older cars using this new design PCV valve.


----------



## ranger1977 (May 13, 2011)

I'm glad I saw this thread. My '07 Silverado uses a quart before the next oil change is due. Can this be covered under warranty?


----------

