Originally posted by Michael
If they are the original '88 guides, be advised that the material used has been upgraded 3-4 times since your car was built. Also, M103s are tough on guides given the way the valves are actuated - I understand there are a few aggressive angles in there that can be tough on the guides.
It is common knowledge that valve guide wear has always been a problem on M103 engines. I believe the "aggressive angle" is also referred to as valve stem/quide side force [ cam-valve swipe].
I agree with the others in that it would be foolish to not replace the valve guides and seals since you are going to the trouble of removing the head. Valve seals can be replaced without removing the head, but not valve guides.
2001 E430, Bourdeaux Red, Oyster interior.
1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".