Mom has an '06 Lucerne with the 3800. It has 34k miles, but it is losing oil way too quickly on the stick. The engine is dry, underneath is dry, no sign of oil in radiator similar to intake gasket type leak, no signs of smoke/buring oil...... What else could it be?

they use about a quart every 3k, which is normal. how much is it?

Remove spark plugs and if any have oil contamination, and the pcv valve is ok, this bulletin may apply.


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)

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


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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 3 200 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(*) 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
 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 ID: 1718359Click here for detailed picture of the image.
(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.


KEEP IN MIND GM CONSIDERS NORMAL USAGE 1 QT EVERY 2K MILES NORMAL.

Agree with Chevy82......the rings on the seals break, oil sucked into cylinders....

If oil is being sucked into cylinders then it appears there would be visible signs of smoke when running. Nothing of this nature. It seems to use a quart every 1500 - 2000. She had another Lucerne that got wrecked and it did not consume oil like this.... I hope it'* not a valve problem, shes only had it a year.....

there other common 3800 leaks were it gets burned on the outside, like the oil sensor seal or if its leaking out the lim end gaskets. if its just leaking a little bit on to something hot you wont be able to see it good, you will just catch a wiff of it when the engine has been running and you open the hood. take the engine cover off and throw it in the garbage and look at those spots

That'* just it everything is dry and I see no leaks anywhere.

its got be going somewhere. either into the engine being burned or outside

You will not necessarily see blue smoke coming from the exhaust, on a leak at the seals, unless it is catastrophic...

Chevy 82'* service bulletin is for 2005 to 2008 year models. I've got a 2001 Park Avenue that is going through a quart between 1500 and 2000 miles. No apparent leaks around valve covers, at least the front one. No oil spots on the ground where I regularly park. No oil fouled plugs..... Car has about 117,000 miles