Last week I replaced the valve guide seals on my 89 405 S 5spd.
The car was smoking so bad that I was afraid there was more wrong with it than
these seals. So bad infact that I have been lead to believe it
was responsible for my catalytic converter plugging to the point that
I had less than 50% of my engine power available. After I chopped the
guts out of the Cat the car really flew but the oil consumption was even worse.
Replacing the seals seems to have corrected the problem. I am aware that
there was some assembly line problem and the guides were reamed off center
causing the seals to wear prematurely. I decided that doing the proper fix
was
to much time and money ie removing the head, installing new guides,
regrinding the
the seats and valves, all new adjusting shims and head gasket. So I made a
tool to compress the valve springs in the head so I could remove the
keepers and get at
the seals and change them. The old seals were hard and brittle almost like
they had been burnt. Most came out with difficulty and in several pieces
this was
the hardest part of the job because of the way they are down in a hole.
Before I do it again I will make a forked foot to attach to my slide hammer
so I can
wack the seals up off the guides. As soon as I track down the timing belt
tensioners
I'll put in a new belt and it should be good for 100,000 km.
Bob Bruce 89 405s Mi16, DL & S