replacing the valve steam seals on my 300e

[luvmuzik66]

Originally Posted by therichzone I acquired a 1989 300ce with 120,000 miles on it last December. I didn’t know the car had an extreme drinking problem when I bought it. It’s going through a quart of synthetic oil around 200 miles. The obvious diagnosis would be a new set of Valve Stem Seals but it doesn’t have all symptoms you would expect to see with bad seals. I haven’t noticed any smoke coming out the back, it passed CA smog a month ago, there’s no oil on the tip of the tail pipe and no exhaust smoke residue on the paint. The car is not leaking motor oil and there is no oil in the water. The only solid symptom I’ve noticed that points to bad valve stem seals is the sparkplugs. The plugs that were in the car were caked with gunk and wet with oil. I changed the plugs and rechecked them after I drove 30 miles and the plugs were wet and smelled like burnt oil and gas i.e. rich. Also the exhaust smells rich to me I’m going to do a couple of thing to better pin-point the diagnosis. I’m going to have a friend follow me on the freeway to find out if it’s blowing smoke I can't see at hwy speeds. I’m also going to check the rings with a compression test. Can anyone suggest any other simple test I can do to diagnose my oil-oholic car before I dig into the motor? Thank you, Let someone follow you on the freeway. If your stem seals are worn, there will be smoke coming out the exhaust every time you punch the throttle (acceleration) and when you decelerate. You will also notice smoke evry time you star up in the morning. The seals are not so hard to replace if you have the right tools and patience.

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[pifcat2]

Originally Posted by therichzone

I acquired a 1989 300ce with 120,000 miles on it last December. I didn’t know the car had an extreme drinking problem when I bought it. It’s going through a quart of synthetic oil around 200 miles. The obvious diagnosis would be a new set of Valve Stem Seals but it doesn’t have all symptoms you would expect to see with bad seals.

I haven’t noticed any smoke coming out the back, it passed CA smog a month ago, there’s no oil on the tip of the tail pipe and no exhaust smoke residue on the paint. The car is not leaking motor oil and there is no oil in the water.

The only solid symptom I’ve noticed that points to bad valve stem seals is the sparkplugs. The plugs that were in the car were caked with gunk and wet with oil. I changed the plugs and rechecked them after I drove 30 miles and the plugs were wet and smelled like burnt oil and gas i.e. rich. Also the exhaust smells rich to me

I’m going to do a couple of thing to better pin-point the diagnosis. I’m going to have a friend follow me on the freeway to find out if it’s blowing smoke I can't see at hwy speeds. I’m also going to check the rings with a compression test. Can anyone suggest any other simple test I can do to diagnose my oil-oholic car before I dig into the motor?



Thank you,

You realize the oil has to go somewhere, maybe a small amount from leaks and burning out the tail pipe. There shouldn't be much oil in the chamber unless it's leaking through the valve seals. Check for leaks again, oil collects on the bottom tray and can leak horizontally along the engine and drip toward the transmission. Do you have a clean driveway?

[restore90300e]

I have a 90 300e that had the same problem (high oil consumption, fouled plugs). The problems got progressively worse from 130,000 miles to 165,000 miles until I got a valve job (approx 1500$ money well spent). The oil consumption droppen to approx 1/2 quart every 7,000 miles (acceptable to me as this is probably caused from other gaskets other than head). I was told the valve guides are the real problem and need to be replaced, as changing the seals only is a temp fix at best. The bottom end of this engine is quite durable and rings are not the likely cause. Spend the money if you are going to keep this car. I learned a lesson on the purchased of this car, that is do the research before purchase. The oil problem on this model is common and I could have used this info in establishing a purchase price if I had done my homework. Good luck and bite the bullet. I would rather drive my 20 year old Mercedes than most new 500$ per month cars.

[pifcat2]

Originally Posted by restore90300e

I have a 90 300e that had the same problem (high oil consumption, fouled plugs). The problems got progressively worse from 130,000 miles to 165,000 miles until I got a valve job (approx 1500$ money well spent). The oil consumption droppen to approx 1/2 quart every 7,000 miles (acceptable to me as this is probably caused from other gaskets other than head). I was told the valve guides are the real problem and need to be replaced, as changing the seals only is a temp fix at best. The bottom end of this engine is quite durable and rings are not the likely cause. Spend the money if you are going to keep this car. I learned a lesson on the purchased of this car, that is do the research before purchase. The oil problem on this model is common and I could have used this info in establishing a purchase price if I had done my homework. Good luck and bite the bullet. I would rather drive my 20 year old Mercedes than most new 500$ per month cars.

Good points, the valve seal replacement (without head removal) is a partial fix until you are ready for a valve job. Apparently the m103 valve train has more side loads so wear is likely through the whole stem.

[johnjzjz]

in my shop we have found the early material used on the valve guides was too soft, and wore the guide oval shaped, than the seal started to leak as if its not their, the problem will not go away till the guides are replaced and the valves are re machined and new seals installed, Syn oil makes it even worse as its thins out more than dyno oil, we put 10 / 40 and lucas oil treatment in the cars that have over 125,000 miles and it helps - the cats on the car burn off the oil consumpion ( reasion you dont see smoke ) till they become clogged and the car looses power and in most cases overheats, blowing out head gasket some shops do a radiator and then well thats not it, lets do a head job and they drag your wallet around the block a few times, rings in this motor are never a thing till the motor has 200,000 miles or so - jz

[therichzone]

Originally Posted by luvmuzik66

Let someone follow you on the freeway. If your stem seals are worn, there will be smoke coming out the exhaust every time you punch the throttle (acceleration) and when you decelerate. You will also notice smoke evry time you star up in the morning. The seals are not so hard to replace if you have the right tools and patience.

A couple of days ago I had a friend drive my car on the freeway as I followed in her car. I didn't see ANY smoke coming out the tail pipe. I asked her to drive it like she stole it but she just cruised like an old lady and never stomped on the gas. We'll do the freeway thing again here soon.

Before I dig into the motor, I'm going to try a "hot soak" with Seafoam and also flush the crankcase with SF - hopefully I'll get lucky. I did 14 hour hot soak (recommended time – 10 minutes) with Seafoam on my old 1989 535is BWM. That Bemmer smoked like Cheech & Chong for 2 days and pissed off a few fanatical greenies. The car ran noticeably better, got better gas mileage and the stuff is EPA approved in CA.

http://video.google.com/videoplay?do...=seafoam&hl=en

[therichzone]

Originally Posted by pifcat2

You realize the oil has to go somewhere, maybe a small amount from leaks and burning out the tail pipe. There shouldn't be much oil in the chamber unless it's leaking through the valve seals. Check for leaks again, oil collects on the bottom tray and can leak horizontally along the engine and drip toward the transmission. Do you have a clean driveway?

My driveway is clean of motor oil - I've thoroughly inspected the engine for leaks several times and the only thing leaking is my power steering pump and it's not leak that much

[therichzone]

Originally Posted by johnjzjz

in my shop we have found the early material used on the valve guides was too soft, and wore the guide oval shaped, than the seal started to leak as if its not their, the problem will not go away till the guides are replaced and the valves are re machined and new seals installed, Syn oil makes it even worse as its thins out more than dyno oil, we put 10 / 40 and lucas oil treatment in the cars that have over 125,000 miles and it helps - the cats on the car burn off the oil consumpion ( reasion you dont see smoke ) till they become clogged and the car looses power and in most cases overheats, blowing out head gasket some shops do a radiator and then well thats not it, lets do a head job and they drag your wallet around the block a few times, rings in this motor are never a thing till the motor has 200,000 miles or so - jz

Thank you, JZ for chiming in. It’s obvious you know what you’re talking about. I’m probably going to do what you prescribe but I’m going try to avoid taking my car to a MB shop and spending $1,500 like restore90300e did.

“Ron in SC” posted some excellent instructions above http://www.mercedesshop.com/Wikka/M103ValveSeals on how to replace the valve seals and I was told on another MB forum that the instructions would be the same on my 89 300ce with a 3.0 L M103motor (I would love some confirmation)

Replacing the valve guides and resurfacing valve ports/head is a lot more work then replacing just the valve seals. Can anyone give me any detailed insights on replacing the valve guides and pulling the head?

You said the original material used on the valve guides (did you mean seals) was too soft – is there a preferred brand of valve guides/seals/gasket etc. you would recommend and do you know a place I can buy them along with the rest of the parts I’ll need at a bargain price?

Here’s a video of machine shop close to me – do you think this is the kinda machine shop I should be looking for? http://www.youtube.com/watch?v=d85obflUSaE If not, what should I be looking for in a machine shop?


As always, I appreciate all the input I can get

[Smedley]

I understand there was a production up grade on the valve guides during the 89 year model run to the more durable type. What is the production date on you car? Smedley

If you find yourself in a fair fight, you haven't been trained properly .

[johnjzjz]

all the guides they sell now are of a much better material than in the 80s stuff, and the type of seal retention and the type of rubber is also different

i was referring too the valve guide material not the seal ( soft )

http://www.autohausaz.com/ this site has good prices if you can get all you need up front its fine but for us a week out on parts is no good i have a local parts store that has great MB Audi VW and alike and they have almost the same pricing less the shipping for me and its that day or the next

doing a valve job is what you are asking is a big deal for a novice, without having a real guy to help who has done it before and has real knowledge of what is entailed as well as some of the special tools needed i would not say go for it - unless the car is a hobby and something you have a real want to learn and try -- jz

[pmally]

hey guys well i still have the 300E sitting in my driveway and everything you all have said about the oil usage problem makes me surely think its the valve guides that are worn out I definitely want to fix the car because its a hell of nice car and i would love to be driving it rather than my old 82 300sd so I am gonna pull the head and take it to the local college when I take engine restoration class next semester. and get it all done practically for free!

[RHW]

HEY! What happened to the new Hondog?

[pmally]

UPDATE: Well I'm enrolled in the engine reconditioning class at Sierra College in Rocklin California (its about 80 miles from San Francisco for thoes that don't know)

Well I just got finished pulling the head off my engine, I was very Very VERY! HAPPY to find that the cylinders all look great no scratches or anything on the cylinder walls. I had performed a compression test previously and I was getting about 120 PSI but after looking at the worn out valves I think that they were leaking air so I was unable to reach peak compression. As for the Valve guides they are pretty bad you can slightly giggle the valves around and everything is black from burnt oil. I had installed new valve guide seals, Its a WASTE OF TIME !! if you car is burning oil just pull the head and get it fixed the right way!

Today at school I am going to dissemble the head, thermal wash it and sand blast it then I will check it for cracks, and also measure the valve guide diameter. I will post what the measurements are and what they need to be. I would like to make a DIY article on removing valve guides, because you could actually do this at home... Its not hard at all...

Also for anyone that needs a service manual the college has the best one Ive ever seen I am going to copy it and turn it into a PDF for anyone that wants a copy, I will also have one for the 300SD 1981 and up.

one last thing anyone have a transmission for the 86 300E?? or know where to get one mine is kinda leaking alot and starting to not shift right. If im going to do all this work on the engine I might as well have a good transmission

[ps2cho]

The valve stem seals are simply a bandaid solution. Before I completely rebuild my 300TE's head, the valve stem seals stopped oil consumption from 1 quart every 500miles to nothing. My valve guides were toast when I pulled the head though. The early w124's ALL have this problem.....My 260E I just found out yesterday has the same problem.

Restore90300E: I know his post was 2/9/2009, but I want to clarify -- With a PROPERLY done valve job, there should be ZERO oil consumption. Period. I run 10-30 in my 300TE right now and its been 3500 miles since my last oil change and it has not lost a single drop. Not one even with the real light oil. I wanted to make this clear for everybody.