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1991 300TE
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54 Posts
Discussion Starter #1
I think the time has come to take action on the mess under the hood.

My 92 TE uses/looses about half a liter every 800-1000 miles. When I leave it sitting after a long run the oil that gets blown on to the Catalytic Converter -smokes like it's about to burst into flames - enough for people to tell me my car's on fire.

As my drive to work is 110 miles each way - its starting to get expensive - though I still average about 24-27 miles a gallon. What I thought was just road dirt - accumulation on the rear hatch - turns out to be oil from the exhaust (i assume)

Do I rebuild or replace. I have 241,000 on the old girl now and I am wondering what makes the best financial decision.

I am in Bel Air, MD. Can anyone recommend a decent shop to rebuild the motor or should I just get a Jasper replacement. Funds are limited. Anyone any idea on what it might all cost. I am not opposed to putting in a motor out of another w124 but worry that I have no proof of condition...blah blah blah..

It's a gasoline motor. Thanks for any advice...
 

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W124
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4,756 Posts
There are a couple of things to consider such as a blown head gasket causing the oil leak that is causing the smoking, and bad valve guides causing the additional oil consumption. Both of these problems are not just common, they are expected on these cars. Luckily both of these problems can be cured by having a cylinder head reconditioning performed.

The bottom end on these motors is stout and rarely is the reason for an engine failure. Additionally, they are extremely expensive to rebuild so I would be suspicious of any economical rebuild of the lower end - even a Jasper.

Ultimately, if the car needs an engine you would be looking at a minimum of $4000 just to have the engine rebuilt correctly by a reputable shop and that doesn't include pulling it or reinstalling it. In reality, with over 200k on the car, if you needed another motor, the best way to go is to buy a parts car with a good motor and just do the swap or have it done. You should be able to find a fantastic donor car for under $1000.
 

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'91 C124 300CE, '06 W164 ML500, '00 BMW MCOUPE, '65 COBRA REPL.
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547 Posts
Ditto on the valve seals.
The most likely culprit as they are allowing oil to pass through thus enter the exhaust.
Check your coolant tank and see if there is any oil floating. If not, head gasket is maybe ok.
 

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w124, 230E
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26 Posts
The engine and cat are pretty far off from one another, so my guess is the oil on your cat is not from the engine. Is it auto or manual? Or if it is, there are other sources of engine oil than the head gasket - the valve cover gasket is one.

The oil on your rear hatch - if your engine is consuming oil, and the cat is working fine, all the HC from unburnt oil should burn off inside of it, so no oil shall be coming out of your exhaust.

Lastly, when these engines start consuming oil, it is usually the piston rings, not the valve seals. Have the compression checked - what engine is that - a four or a six-cylinder? I know European T models were only four bangers, but I am not sure about the States - you guys always get the better stuff :).
 

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'91 C124 300CE, '06 W164 ML500, '00 BMW MCOUPE, '65 COBRA REPL.
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547 Posts
You could be right about oil leaks causing these issues as well. Oil drips on to the headers/exhaust, car starts and exhaust gets hot thus burning the oil and thus the smoking car.
 

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Premium Member
99 SLK230 Kompressor, 5 Speed Manual
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1,117 Posts
Does it smoke on cold startup? If so, it might only be valve guides and seals. The bottom of these engines is usually good for several valve jobs before requiring attention. This statement applies if it has had reasonable oil change intervals and not driven crazy.

Do a compression test. If the compression is good, a valve job including new valve guides will most likely get it back in shape.
 
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