mckay

I noticed a bit of oil in the O2 sensor connectors when I replaced them, yet didn't think much of it as it was only a small amount, cleaned them and installed.

My car has been needing < 1L of oil per 15K kms, nothing major, yet enough that I wanted to find the source.

Looked into other oil leaks on the W203 and saw the cam magnet sensors have leaked on the M111 causing oil to get into the harness.
I checked, and there's oil in the cam magnet sensors on my M271.
There is also oil in the ECU and MAF connectors, none in the other connectors so far.

Can someone do me a favor:
- pop the connectors off and look to see if there's oil on them.
- the magnets are circled in orange in this pic:

mckay

Confirmed with the dealer - the cam magnet sensors are leaking on high mileage M271 engines.

Its a $500 part and 6hrs of labour to replace the engine harness.

The typical failures are the O2 sensors as the oil destroys the sending units.

So far this year:
$300 MAF
$250 for both O2 sensors

Now:
$100 cam magnet sensors
$500 engine harness
$250 possibly new O2 sensors since the CEL is back

Boom vang

I just had a major oil leak (covered by warantee) at the cam sensors. Oil was everywhere. My engine was a low mileage unit with 52,000km (31,000mi) I think that the problem was when they replaced one of the sensors under warantee because of an error code

mckay

Well I am at 130K and not covered by warranty anymore, so I am looking to fix this myself.

mckay

There is apparently a cable that isolates the cam sensor from the wire harness. There is definitely one for the M111, yet on the MB UK forums there is talk of one for the M271 starting with a A271 part number, yet the full part number was never posted.

Anyone with a repair bill for this for the M271, could you check to see if you can find a part for a cam wire harness extension starting with A271

Thanks.

Boom vang

I will be getting my workorder on Wednesday from the warantee repair work so I can send you the number if they put on the harness extension

mckay

Thanks, could you also ask for what "number" your engine is.

My engine is a 271.740, the TSB is for the 271.747, and the 747 has different part numbers for the cam magnet sensors so my dealer is unsure if the cable will work on my car.

Its $40 so I ordered it anyways. Will get it Weds and report back then.

Boom vang

how do I know what engine I have?

mckay

Not sure, might have to ask your dealer who will look it up in the system... or it'll be written in the engine bay or door jam...???

Try this:
http://www.mbclub.ru/mb/vin/?lng=eng
My engine code came back as this: 271948 30 035616

Boom vang

my engine is 271948 30 226949 but it still does not tell me if it is a .740 or .747