response....started just since the last oil change....no towing last round....had to add 4 quarts after about 5000 miles and was getting ready for an oil change even though the oil life read 30%
UPDATE #1....below is what i found on trackshare.com.....I don't know how to find out if there have been updated PI or PIP's? Does anybody know where you can track these PIP's for updates??
#PIP4574E: Excessive Oil Consumption And/Or Blue Exhaust Smoke - keywords BQMI - (Jun 19, 2009)
Subject: Excessive Oil Consumption and/or Blue Exhaust Smoke
Models: 2007 Chevrolet Avalanche, Silverado, Suburban, Tahoe
2007 GMC Sierra, Yukon
with 5.3L Engine (RPO LC9 - VIN 3)
This PI was superseded to update Recommendation/Instructions. Please discard PIP4574D.
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Some customers may complain that their vehicle has been using approximately 1 quart of oil every 500-1,000 miles. In most cases, the customer will advise that this did not start until it accumulated approximately 20,000 miles or more and no engine performance concerns will be noticed. They may also complain of occasional blue exhaust smoke.
In many cases, technicians have performed SI diagnosis, compression tests, and cylinder leakage tests with no problem found. Several vehicles with this complaint have had valve covers, lifters, complete cylinder heads, and/or stuck oil control rings replaced only to have the vehicle return with the same concern again.
As a result, PIP4574 was created on 2/5/2009 to explain that the cause of this concern is under investigation.
Since that time, engineering has inspected multiple engines that have been replaced for this concern and have also inspected multiple trucks with this complaint but have not found one common cause for this concern. And, with the help of many dealerships, engineering was able to collect a lot of information about this concern using the oil consumption checklist that was in PIP4574C.
At this point, the cause of this concern is still under investigation but the recommendations below have been updated to reflect everything that has been learned so far.
We really appreciate your help and patience with this and we want to assure you that this PI will be updated as soon as more information is available.
If a customer has this complaint, perform the steps below, document your results in the oil consumption checklist below, and attach the checklist to the repair order in case it is necessary for future reference:
1. Visually inspect the entire engine and the underside of the vehicle for any evidence of oil leaks and repair them as necessary.
2. Inspect the fresh air hose/pipe that is attached to the RF (passenger side) valve cover and all related connections for restrictions, such as plastic casting flash or a pinched hose, and repair as necessary. A restriction in this area may cause excessive crankcase vacuum and oil consumption through the PCV vacuum tube.
3. Perform an oil consumption test as outlined in the latest version of oil consumption of 01-06-01-011. Allow the vehicle to sit on a level surface with the engine off for at least 10 minutes to allow the entire engine to drain back to the oil pan before checking the engine oil level and adding oil. Match the oil consumption test results to one of the outcomes below to determine further direction:
• If oil consumption is Less than 1 quart of oil every 2,000 miles and no low oil light has been experienced, no repairs should be performed as this should be considered acceptable oil consumption as outlined in the latest version of 01-06-01-011.
• If oil consumption is Less than 1 quart of oil every 2,000 miles but the customer has experienced a low oil light, refer to the latest version of PIP3959 for a potential low oil light sensor concern.
• If the dealership verifies that oil consumption is More than 1 quart every 2,000 miles, perform the steps below as necessary:
4. Remove the LH (driver's side) valve cover and inspect the PCV baffle drain holes shown below to see if they are plugged with hardened oil deposits. If they are plugged, replace the valve cover, ensure that the customer is changing their oil according to the maintenance schedule in their owner's manual, and re-evaluate the concern. Generally, this would not be a concern until several thousand miles have accumulated.
Object Number: 2195879 Size: SH
Click here for detailed picture of above image.
5. With the LH (driver's side) valve cover removed, inspect the PCV baffle to ensure that it is properly sealed to the valve cover by flipping it over and adding a little oil to the corner of the valve cover as shown below. The oil should stay in place as shown on the 2 outer valve covers below. If the oil drains into the PCV baffle as pointed out on the middle valve cover below, replace the valve cover. Generally, if this is the cause of the concern, it would have been present early in the life of the vehicle or shortly after valve cover replacement.
Object Number: 2245145 Size: SH
Click here for detailed picture of above image.
Important: If Step 4 or 5 led to valve cover replacement, perform Step 5 again on the replacement valve cover before installing it.
6. With the LH (driver's side) valve cover removed, carefully check for an over-aggressive lifter by monitoring oil flow at the top of each push rod with the engine at idle. Very little flow should be observed at an idle. It will be obvious if an over-aggressive lifter is present because its flow will be greatly excessive when compared with the others and a great deal of cleanup will be required. If okay, perform the inspection a couple more times but momentarily raise the RPM off idle for a couple of seconds and let it return to idle before inspecting the oil flow at idle. If an over-aggressive lifter is present, replace all of the lifters on the driver's side bank and re-evaluate the concern.
Notice: If you verify that oil consumption is More than 1 quart every 2,000 miles and all of the suggestions above have been performed without isolating the cause of this or decreasing the oil consumption rate to an acceptable rate (less than 1 quart every 2,000 miles), do not attempt additional repairs at this time. The cause of this concern is under investigation and this PI will be updated with additional details as soon as they become available.
Edited by headnorth, 18 May 2010 - 08:14 AM.