Mechanics

OIL CONSUMPTION FOR 3.8 L - WHAT IS NORM

2007 Buick Lucerne

Engine Mechanical problem
2007 Buick Lucerne 6 cyl Front Wheel Drive Automatic 44500 miles

During the last 7K miles the engine has been comsuming ~ 1 3/4 quarts of oil every 3500 miles. The dealer tells me that this is normal and I should expect 1 quart / 2K Miles which I consider ridiculous on such a young engine. I did some research on the net but no true results to answer this question. Is there a quite service bulletin I should know about. Currently working with the dealer to do an oil consumption test.
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Johnmi4455
May 5, 2010.



Subject: L26, L32, L36, L67 Excessive Oil Consumption (Replace Exhaust Valve Stem Seals)

Models: 2005 Buick LeSabre, Park Avenue
2005-2008 Buick Allure (Canada Only), LaCrosse
2006-2008 Buick Lucerne
2005 Chevrolet Impala, Monte Carlo
2005 Pontiac Bonneville
2005-2008 Pontiac Grand Prix

with 3800 Series II, III V6 Engine (VINs 2, 4, K, 1 - RPOs L26, L32, L36, L67)

Supercede: This bulletin is being revised to update the model years. Please discard Corporate Bulletin Number 05-06-01-035 (Section 06 - Engine/Propulsion System).

Condition

Some customers may comment on excessive oil consumption on 3800 Series II and Series III engines. An engine that has excessive oil consumption uses 0.9L (1 qt) of oil or more within 3200 km (2,000 mi).

Cause

This condition may be caused by the retaining ring on the exhaust valve stem seal not securely holding the seal on the cylinder head boss. If this occurs, the exhaust valve stem seal(s) may move off the cylinder head boss and no longer provide a sealing function between the exhaust valve stem and the valve guide.

Correction

Inspection and/or Replacement of Exhaust Valve Stem Seals

Follow the appropriate Service Information for the vehicle you are working on to gain access to cylinder head exhaust valves on both cylinder banks. Remove the engine valve rocker arm covers, the exhaust rocker arms and the exhaust valve springs.

Oversize valve stem seals are available. Make sure the correct valve stem seals are installed. An OIL CONSUMPTION concern can be created by installing the oversize valve stem seals. The oversize valve stem seals are marked black in color and are NOT to be used UNLESS installing valves with oversize valve stems.

There are 2 different valve stem seals used - one for exhaust valves and one for intake valves. Exhaust valve stem seals are green in color and have " EX" molded into the top of the seal. Intake valve stem seals are blue in color and have " IN" molded into the top of the seal. Using the wrong seal on a exhaust or intake valve can also contribute to oil consumption. The correct seal usage should be verified while checking for correctly seated exhaust valve stem seals.

Correctly Installed Exhaust Valve Stem Seal

Incorrectly Installed Exhaust Stem Seal (the seal is not seated on the valve guide and the cylinder head boss.) Carefully inspect each exhaust valve stem seal for engagement on the exhaust valve guide (refer to the previous illustration). If one or more exhaust valve seals is found to be incorrectly installed, replace all the exhaust valve seals. If no trouble is found with the exhaust valve seal seating or usage, refer to the service manual Oil Consumption Diagnosis to investigate other sources of oil consumption.
Might want to ask them if they looked at this bulletin, maybe follow this first.

Brian 1
May 6, 2010.
First let me say thank you for the detail response. Excellent. What is the current Bulletin number?

Tiny
Johnmi4455
May 7, 2010.
#05-06-01-035A

Brian 1
May 7, 2010.
Afternoon; It has been about a year and the repair mentioned early (Replacement of Exhaust Valve Stem Seals) was preformed. About 13,000 miles later the same problem is occuring again. Just as last time when approaching an oil change (~4000 after last oil change) the engine was down 1 1/2 quarts of oil. Performing an oil check with the dealer now. After 750 miles down ~ 1/3 of quart of oil. Waiting for the next 1000 miles to occur to see what happens. I keep getting told theat 1 quart of oil for 2000 miles is coomon and I don't buy it. What course of action next?

Tiny
Johnmi4455
Jun 13, 2011.