There has been alot of discussion about valve guides on M103 engines on this board.
I recently spoke with a mechanic about an oil consumption problem on my 1989 260 E with 76,000 miles on it. The car burns about three quarts of oil every 3000 miles.
He told me that the valve guides are absolutely bad on the car and that I must do a full valve job on the car to solve this problem.
Another mechanic told me that, yes, M103 engines do have valve guide problems, but that at only 76,000 miles, more likely than not, the valve guide SEALS have gotten brittle and that the guides are not yet bad. He said that he would just replace the valve guide seals and check the guides for play when he did this and that if they did not have play, it would be a waste to do a full valve job at this point in time. His price to replace valve guide seals only: $300.00
The first mechanic's price for a full valve job $1500.00
I told the first mechanic what the second mechanic had said, and he said that the second mechanic did not know what he was talking about and that the reason the valve guide seals would have gone bad in the first place was BECAUSE the guides had so much movement against them.
Both of these mechanics have worked on Mercedes-Benz for over 15 years each.
My questions are as follows:
1) Is it possible that my valve guide seals have gotten brittle but that my valve guides are fine?
2) Can a valve guide with play really cause a valve guide seal to go bad?
3) Is the first mechanic just trying to sell me an unnecessary valve job?
4) In what years did MB modify the valve seals and/or guides in the M103 engines? I read somewhere that 1986 and 1987 engines had valve guide seals made of one material and that 1988 and newer seals were made of more durable viton. I also have been told that the valve guides themselves to the 1991 and 1992 engines were stronger than in previous years.
5) Do M104 engines have weak valve guides and seals as well? (Since the head is totally different, I didn't know whether these engines shared the same valve guides and seals.
Thanks in advance!