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Dave Nova
Dave Nova, Buick Technician
Category: Buick
Satisfied Customers: 19452
Experience:  ASE Master Certification. GM World Class Certification
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why does the3.8 motor use oil so bad my car has 21000

Resolved Question:

why does the3.8 motor use oil so bad? my car has 21000
Submitted: 7 years ago.
Category: Buick
Expert:  Dave Nova replied 7 years ago.
How much oil does it use? At what mileage intervals?
Customer: replied 7 years ago.
I have had other gm cars and they did not use oil but gm tell me normal for 3.8 to use a quart every 2200 miles
Expert:  Dave Nova replied 7 years ago.

Some engines will use almost no oil, while others will use some. If you are using a quart every 2200 miles, this is not considered excessive.


DEFINITION: Excessive oil consumption (not due to leaks) is the use of 0.946 L (1 qt) or more of engine oil within 3 200 km (2,000 mi).

Customer: replied 7 years ago.
that is not normal, i was a mech my self and i never saw a car that used that much unless the morter was bad
Expert:  Dave Nova replied 7 years ago.

In my opinion, the engine should not use that much oil, but according to GM, it is within their guidelines. There is a technical service bulletin out that deals with exhaust valve stem seals on this engine that may not stay in place, causing excessive oil consumption. I have included this bulletin for you.


#05-06-01-035A: L26, L32, L36, L67 Excessive Oil Consumption (Replace Exhaust Valve Stem Seals) - (Oct 2, 2007)

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)


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


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 3 200 km (2,000 mi).


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.


Inspection and/or Replacement of Exhaust Valve Stem Seals

  1. 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.

    Notice: 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.

    Notice: 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.

    Object Number:(NNN) NNN-NNNN Size: SH

    (1)Correctly Installed Exhaust Valve Stem Seal
    (2)Incorrectly Installed Exhaust Stem Seal (the seal is not seated on the valve guide and the cylinder head boss.)
  2. 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.
  3. 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.
  4. Parts Information

    Part Number



    *Seal, Exhaust Valve

    *Exhaust valve seals are five seals to a package. An additional package will be needed so all six exhaust valve seals are replaced.

Customer: replied 7 years ago.
thank you,one more queston, could this be caused by bad oil rings
Expert:  Dave Nova replied 7 years ago.

While this is a possibility, it is not likely. Ring sealing technology has come a long way and we don't see many problems with this. The exhaust valve stem seal problem is common on this engine.

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