300e oil usage (again)
 

My situation is as follows:

1991 300e 4matic with 76k miles. Uses about 1 qt of oil per 1,000 miles. My search of the archives on this topic seems to suggest that:

1) At some point in time, the valve guides and seals will need to be replaced (do them both at the same time, as replacing the seals alone will not fix the problem for very long).

2) In the interim, there could be some benefit in using some type of high-mileage oil formulation. It seems in order of effectiveness on this car, it's Castrol High Mileage first, Valvoline Max Life a close second, and the Pennzoil product a distant third.

Anybody disagree with this?

Thanks

Jay

Stevebfl frequently posts that on M103 engines, valve seals should be replaced about every 90,000 miles. Valve seals only, not valve guides. This is good news as valve seals are much cheaper to do because the head doesn't need to be removed. Replacing valve guides requires the head to be removed.

http://www.peachparts.com/shopforum/tech-help/55949-any-m103-owners-go-past-150k-miles-without-valve-job.html#post335087

I was in the same boat as you are. Just purchased my 300 and got a big suprise when the oil light came on after a couple weeks of use. My car was around 76k miles also. Mechanic said it was the valve guide seals and replaced them. The parts are so cheap . . . I mean inexpensive. He said that the first time they need to be changed is around 75k miles. He also stated that MB knows they are a problem and has changed them somewhat so that now they will last around 100k miles, (after changing them the first time). Haven't used a drop of extra oil since.

Jay

I think that is close to right on here, except: Are you sure that is where your oil is going?

I found out that my real oil consumption with the '91 300E was the upper front engine cover.

We got it at 129k, it now has 200k and the more I use the oils you describe, the better the consumption is. At the worse, it was about a 1 qt in 1,200 miles. The best is at around 1 qt in 2,800 miles.

The plugs remain oil free which to me points to: the stem seals are not leaking, they must have been replaced prior to my purchase ? or maybe not?!

I was told by an old Porsche tech years ago that it is the valve guides and the seals that tell the true initial story of how well a car is taken care of. If you run it gently until it warms up (no hard driving or high revs) AND you change your oil and filter appropriately with your driving habits, you should have minimal guide and seal problems.

It is hard to say where this good advice insects guides and seals that should have been made better, but I thought I would pass it along.

Haasman