Oil leak (?) in S320

Dr Buz

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Hi,

Today I had the pleasure of having a test drive of a W140 S320 registered in 1996 with circa 63,000 miles. There were three issues that I noted and I wondered whether anyone could enlighten me? Thanks.

a) There was apparently a small oil leak that had been going on for some time. It seemed to originate from the top, front of the engine (perhaps around about the water pump area?). However, the oil had leaked down the nearside of the engine block which was covered in a sheen of oil, as was the upper side of the plastic engine cover (the one under the car that covers the sump). Also the front suspension crossmember under the car was covered in this sheen of oil. The leak had been going on for some time because there was a lot of road muck stuck to it. I also noted that from the dipstick that the oil level was overfilled.

So my questions are:

1) Could this oil be coming from a failing head gasket? The coolant did not seem to be contaminated.
2) Would overfilling this engine cause excess oil to be ejected from the top front area of the motor?
3) Are the 6 cylinder 320 prone to leaking oil?
4) Any other suggestions?

Bear in mind that I have a C180 and the front of that engine is slightly coated in oil from perhaps the water pump area. Strangely though, having changed the oil to Mobil 1 0W/40 (the thinnest oil that I have ever used), the leak has stopped!!! My C180 has 119,000 miles.

b) When I was under the S320 with the engine running, I could see the torque convertor spinning. Is this correct? Should there be a blanking plug over the hole? I know that the hole is there to allow acces to the drain plug in the convertor but surely this hole would be filled with a cover/plug? Should there be a protective cover over the gearbox?

c) There was some suspension knocking that was either sway bar or drop link.

Many thanks for your help.
Incidentally, I am very mechanically minded and have taken several engines apart along with various other car parts over the years so I have some idea of what goes on.

And I am not going into a purchase of a W140 with my eyes closed so please, no replies along the lines of "if you don't know what this car is then it isn't for me" if you see what I mean. Thank you.
 

kth286

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Your Mercedes
E320 Coupe 95
there was a 1995 TSB for the oil fill on the 104 engines.

It was reduced by half litre and should be NO MORE than half way between MIN and MAX.

It cured my oil weep.
 
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Dr Buz

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Hi,

Thank you for your replies. They are really helpful.

Buz
 

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That is a very low mileage car that you have been looking at,,mechanical faults are much cheaper to deal with than body work
 

Alex Crow

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hi there, for the classic head gasket oil leak you would find most oil down the o/s of the engine, not n/s. if i had to guess, i`d say it`s your front crank seal, not a big job at all. reducing the oil level may attenuate it somewhat, worth a try as a first measure.

yes, there should be a blanking plug at the front of the bell housing (engine sump), with a grille for air flow on the underside of the gearbox bell housing.
 
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Dr Buz

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Hi,

I too was surprised at the mileage. However, the service record checked out. It was complete and FMBSH. There were some receipts for work done.

Other stuff seemed to correspond, like pedal rubbers not too worn, clean engine (despite being boxed in with plastic covers), no rust on upper bodywork and none on underside of bodywork. Just a few spots of rust on the odd suspension component but nothing serious or cause for concern.

CV rubber boots were deteriorating but no splits. Seemed to fit with a car that has done not much mileage.

Tyres were matching.

The suspension issue was mentioned as an advisory on last MOT but I forget whether it said drop links or anti roll bar bushings. Still, not a particularly big job though.

Still, the lack of protective covers/blanking plug on the bell housing makes me wonder whether it's had a new 'box at some time or simply had fluid changed. There were no documents to this effect though I suppose either could have been done a long time ago under warranty. Just a guess?

Very much in two minds as to whether to go ahead. Do I really want one or do I stick with my current workhorse?
 

Alex Crow

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front roll bar links are a pain as the disks and shrouds need to be removed to get to the nuts, although it is easliy do-able for a good DIYer like yourself.
 

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There is no blanking plug in the bell housing, any oil will drain from there from the engine
 

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