I had valve guides and seals replaced on my '91 300SE at 90,000 miles. Now, 30,000 later, it is using oil again (about a quart per 1,000 miles). My new mechanic (I've moved to a different state) tells me that he thinks that the valve guides and seals need replacement, and that 5 of the spark plugs had oil on them. He suspects that the first mechanic may have charged me for valve guides but only replaced the seals.
I suggested that the next time I bring it in, that we replace the seals and see if that works. He said that he didn't think that would work, but he would be willing to try unless the valves have just too much play in them. If that is the case, he would proceed with the valve guide job. He also said that he normally does not replace seals without doing the guides too.
Does it make sense to try just seals?
Is there a standard for valve-to-valve guide clearance? Is it measured or just an acquired "feel"?
Thanks,
Jim W.