Shoul I replace valve stem seals on 103 while apart
 

I have my 1992 190E 2.6 apart replacing the cam seal and upper timing cover seal. It has 172K on it and the seals have never been changed. I noticed what appeared to be oil on the rear bumper after an 80 mph road trip. This forum has been a big help. I recenly adopted this car knowing it would need age related repairs and I have been successful with replacing brakes/rotors, motor mounts, and tie rods. I don't want unecessary frustration, but I'm thinking I should change the seals. anybody have thoughts about this?

If you want to replace them, you are going to need a compressor and a tool like this
http://i135.photobucket.com/albums/q...prnigCompE.jpg
so you can get at the stem seal.

How do the spark plugs look and how much oil are you burning?

M103 oil consumption seems to depend on the oil you use too.....I was using 0w40 mobil synthetic....and it was consuming a quart every 700 miles or so....then I switched to Rotella 5w40 synthetic diesel oil, now it uses about a quart per 1300 miles....major difference.

i would also suspect the valve guides. they are a notorious weak link for mercedes. if 1 or 2 plugs are really fouled, pull those valves apart first and see if you can move the guide up and down or side to side. no movement is allowed. of course, you still need the tool from the above post. good luck, chuck.

Good morning-

While your car may need valve seals, this will not eliminate oil on the exhaust, tail lights or underbody. That is an external oil leak- hopefully you got it with the front cover and camshaft seal... but it might well be a headgasket. It is routine with M103 and M104 engines. Wash the engine good and watch for where it leaks.
There are plenty ppl on the list whom have sucessfully R&R'd valve seals without the specality tool shown.
If you got to pull the head... I'd highly suggest having the valve guides inspected and valves ground(minimum).

Michael

Definitely do the seals while apart. 17 years and 172k is plenty, and valve seals are cheap.

i've done them on a couple of 124's.... however i have only done 5 valves

the passenger side valve back by the firewall was too difficult to do with the tool i borrowed from the auto parts place.

i was burning a qt every 650 in the CE...it is now burning a quart at 1300

our 260e was burning a quart at 350 miles...now more like 1200

Valve stem seals are dirt cheap and can be replaced, as you probably know, without pulling the head. That will help decrease oil consumption.

But you may have other issues too, like a leaking head gasket and worn valve guides that would require pulling the head. As previous posters have said, both were 103 chronic problems.

FWIW, I replaced the valve seals about 4 years ago. It was using a qt. every 500 miles or so. The car had about 75,000 miles on it. Problem solved. I am at 109k now and no significant change in consumption.

Depending on your personal variables, cost, DIY skills, planned length of ownership, try the seals first, clean the block good and watch for external leaks and monitor consumption. Pulling the head can wait a while.....maybe;)

Thanks all for the feedback!! I'm going to go ahead and change the valve stem seals .