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-   -   Front cover leak and 'oil witching' questions (http://www.peachparts.com/shopforum/showthread.php?t=6850)

makakio 03-22-2000 05:38 PM

Hi all,

Have developed an oil seep around the front engine cover (timing chain cover?). From reading here it appears to be typical with the 201s and an easy fix. Anyway, it's slow - no significant pooling (yet) or really noticeable oil loss (yet), just some minor stains in the under-engine cover. My tech says no real need to worry about it at present but said he first suspected some kind of leak when he pulled the oil dipstick while the car was idling. He said that MBZs usually build up a small vacuum in the oil system and if it's a closed (ie no leak) environment the engine should stumble slightly when you first pull the stick (and break the o-ring 'vacuum' seal at he top).

Sounds strange to me. Can anyone add to (or from) this statement?

Also - the car has 69k miles on it and I've read here that the valve guides die prematurely on this model. Does it make sense to fix both at once (save labor charges), or are they two separate jobs?

Thanks

stevebfl 03-22-2000 06:13 PM

Your tech missed on this one. The condition he described exists on many cars but not your MB. MB limits the amount of crankcase scavenging to what can pass through a metered oriface. The amount is considerably more than that which a good engine gives off in blow-by. Because the volume through the oriface is always greater than blow-by a significant vacuum would occur in such a situation. MB balances this by allowing air to flow into the valve cover from the air cleaner. Thus total air flow is blow-by plus intake air at V/C. There is no pressure differential.

BMW, Porsche, some models of Volvo have systems like your tech described but not any of the variety of K-Jet systems used by MB.

------------------
Steve Brotherton
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician

LarryBible 03-23-2000 07:41 AM

makakio,

As to the valve guide portion of your question. You did not say which motor you have. I am assuming that it is a 2.6, if so:

The 2.6 is an M103 engine, little brother to the 3.0 engine in the 300E. I have seen a number of posts claiming valve SEAL problems on these engines. I have an '88 I bought used at 89,000 miles with very thorough records. In the records is a receipt for replacing the valve seals. If there was indeed very high oil usage before they were replaced, I would be amazed.

In fact the engine has done so well, I wonder if it was an independent shop scamming the unsuspecting owner. There were alot of suspicious, expensive repairs done by the same shop. There are many, good, honest shops out there, but there are some scam artists too.

Anyway, the engine now has 169K and uses NO oil. I change it every 3,300 or so and it doesn't even show any loss of oil on the stick during that time.

Maybe one of the pros will comment here. Would replacing only the seals, actually make this much difference?

Because of this engine using no oil, I wonder if the M103 valve seal or guide problem only happens on some cars, or is really prevalent across the breed.

I'll bet that if your car is not showing high oil consumption now, you will probably never see it during the life of the engine.

What do you think pro's?

------------------
Larry Bible
'84 Euro 240D, 516K miles
'88 300E 5 Speed
Over 800,000 miles in
Mercedes automobiles

stevebfl 03-23-2000 08:03 AM

Well here is my experience.

All the 102/103 motors have exceptionally high failure of V/G oil seals. Both the problem and the fix are distinct. Anyone in a hot state that works on these cars can probably tell you how much oil you are using by looking at the plugs that come out of a 15k service. Oil usage in the 500mi/qt to 1000/qt range appear all the time and the plugs will be evenly plated with carbon deposits. A car in this situation can be returned to the 2000+mi/qt condition with the simple V/G seal replacement.

The amount of money to be saved on oil isn't the question here. The real problem here is the build up of carbon on valves and most importantly the catalytic convertors.

------------------
Steve Brotherton
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician

makakio 03-23-2000 12:28 PM

Good answers guys - thank you. The car is indeed a 2.6 and uses a little oil - I add a half-quart between changes at 3k or 3.5k miles. And I run the engine hard. I've read and have been told that the valve seals and guides on these engines are inherently the weak link though the plugs are coming out clean at this point (I didn't know they were an indication of VS and VG wear). That's comforting. If it starts using more oil or the plugs get dirty I think I may have to consider the work. Question remains - will I save some $$ by having both the front cover and top end work done at the same time or are they two different jobs?

jeffsr 03-25-2000 10:22 PM

Can't do the valves w/o the front cover coming off. Your oil comsumption does not sound really excessive at a half quart between changes. Front cover reseal is a small job. Guides and seals require removing the head. ($$Big Job$$)

------------------
Jeff L
1987 300e
1989 300e
1987 BMW 325

[This message has been edited by jeffsr (edited 03-25-2000).]

stevebfl 03-26-2000 01:11 AM

The problem with 102/103 valve guide seals is with the seals not the guides. The head doesn't have to come off.

The labor is about three hours if I recall. There is no reason to do the job till you are using more than a quart every 1000 miles.

------------------
Steve Brotherton
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician

makakio 03-27-2000 11:49 AM

Thanks Steve and Jeff - the advice I was looking for.
Matt


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