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ivan 06-12-2002 04:22 PM

cost of valve stem seals vs. do-it-yourself on '89 300E?
Have an '89 300E with 160K that is starting to show a little black smoke out the tailpipe when following the wife. Uses @1 qt. of oil every 1,000-1,500 miles. Plugs seem fine.

Just got a quote of $570 for valve seals from a foreign car shop. Seems a little high to me. What price should I expect? Is this a job for a moderate DIY? (For perspective, the last head I changed was on a 1957 Studebaker Hawk! Yes, I know the head doesn't come off for the seals.)

If a shop changes the seals, I assume they will check the guides. Is it usual to have to repalce them at this mileage? If so, I know I don't have the tools for that one!

Thanks! :)

mradowic 06-12-2002 05:27 PM

Re: cost of valve stem seals vs. do-it-yourself on '89 300E?
I had a quote for $380 for my valve seals, but then my
head gasket blew and I had to have everything done
at once! Your price seems a tad high though. Hope
this helps.


sixto 06-12-2002 05:43 PM

Replacing the valve seals is not that difficult. The most complex tool you need is the type of valve spring compressor that hooks on the cam.

Don't worry too much about the valve guides. If they're really worn and oil consumption continues or comes back shortly, all you lose is ~$20 in parts and an afternoon. What you gain is time to shop for a good deal on a full valve job.

91 300SE
87 300SDL

ebennz 06-12-2002 05:45 PM


i have a '92 300e w 121k.
at about 102k i had new valve guide oil stem seals put in my car.

it has made a world of difference, the [excess] oil consumption is gone.

mercedes shop brother [ha ha] "stevebfl" aka as steve brotherton owns contiental motors in gainesvill, fl. the job cost around $300.00 + $ 100.00,gas. it was worth it to me. i live in west virginia, but enjoyed the road trip.

where do you live?

have you checked the section "good mb shops"?

i don't know what it would cost to do yourself. i think the difficulty factor is about a 5 out of 10

some of you other guys chime in

also try a "search" on this subject.


ivan 06-12-2002 06:35 PM

Wow, you guys are fast. My earlier search on the subject as a DIY revealed that you had to put compressed air in the cylinders? That was enough to make me look to a shop. Perhaps I misunderstood and that is only necessary to replace the valve stem guides (that one is beyond my level of expertise.)

I'll re-search the "valve stem seal" posts again but if all I need is the proper valve spring compressor, I'm game. I'm in Wilmington, NC which is in SE NC about 60 miles from the SC border. Raleigh is 120 miles away and Charlotte is 180. No good shop recommendaiotns near here that I can find under the "Good M-B Shops" forum.

Thanks, guys; always appreciate your vast collective knowledge. y:D

blackmercedes 06-12-2002 06:43 PM

Are you sure that's your problem?

Your oil consumption is not that high. Most folks get antsy when the rate gets to 1 litre for every 500-600 miles.

Black smoke? Hhhhmm. Blue-ish smoke is from oil buring. Black smoke is from a rich fuel condition.

Make sure you're actually fixing something that's broken...

ivan 06-12-2002 06:47 PM

Thanks John, I'll look at the smoke more closely. It was a little wispy so couldn't tell if blue. An earlier compression test was in the 190's all around.

If too rich, I assume the average handy-man couldn't make the adjustment. Another shop visit? Clogged injectors? Anything else come yto mind if black smoke?


stevebfl 06-12-2002 06:57 PM

Well I was going to add it up but Peter beat me to it.

But, John tells it like it is, a quart every 1000k is OK. Even much more would be acceptable but for the carbon that builds up.

You need to look into the closed loop operation of your O2 sensors.

sixto 06-12-2002 07:08 PM


The most complex tool you need is a valve spring compressor but it's not the only tool you need. You need some way to keep the valves in place while the keepers are off. Compressed air works. Some folks stuff rope through the spark plug hole.

91 300SE
87 300SDL

LarryBible 06-13-2002 02:34 AM

Usually if you are leaking oil past the seals/guides, it will blue smoke at start up and then cease smoking.

Seal replacement would not be a bad idea if you are doing it yourself. That way if it doesn't work, you will not be out very much money.

I agree with the other poster who suspected something else causing the smoke. Is it BLUE smoke?

If I were going to spend over $500, I would go ahead and do a valve job and definitely replace the guides. I would do a compression, or better yet, a leak down test to determine the condition of the engine in particularly the condition of the rings and cylinders before doing the valve job. It still could be something else causing the smoke.

Good luck,

Potomac Pat 06-13-2002 10:15 AM

I am with Larry on this one. If you can't replace the seals yourself and are looking at dropping close to $600. I'd say find another shop and for a few more Franklins get a complete valve job.

stevebfl 06-13-2002 11:42 AM

I just don't understand so much desire to do expensive engine repairs when statistics show absolute success with seal repairs well into the third hundred thousand miles.

The job is 4 hours labor and less than $20 for seals. If you figure that the V/C gasket should be replaced about every 100k, then the extra work to systematically maintain the seals at the same time would only be 3 extra hours labor and less than 20 for seals.

LarryBible 06-13-2002 12:15 PM

I would never doubt Steve. We are lucky to have him sharing his vast experience with us.

From his information, it sounds like the shop that quoted $570 is asking over $150 per hour as their shop rate.

I am sure Steve is right. My experience with replacing seals was not that good, but it was not on an M103 engine either.

Good luck,

stevebfl 06-13-2002 12:47 PM

The actual time by MB flat rate is job 05-3510 and is 3.4 hours. Alldata gives 4.8 hours in their labor guide. We tend to follow MB's guide with minor corrections through experience.

The job takes about 3 hours and can be done in less if one is quick and experienced.

David.kingsbury 08-05-2002 11:54 AM

Four hours to replace the valve seals? No way. I just replaced the seals in my 560 SEL this weekend. I would say more like eight hours. Assuming you do not lose or break any parts.

If you want a rundown on how its done let me know.


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