A1EK

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Hi Guys

My wife has an auto C180, W203 year 2002 and a couple of days ago the yellow engine light came on. The care was sluggish from start and stalled a couple of times, once warm it was okay.

Things I have noticed are that over the last couple of months I can smell a slight oily smell in side the car as it comes through the vents, I have noticed in the engine that the top rubber breather seems to have oil leaking around it.? The oil doesn't smell burnt just normal but I have heard that this could be a symptom of a blockage somewhere else and it is showing at this breather pipe but not sure where to start to look.?

The other point I can mention is that sometimes when you start from cold the revs climb up and down by themselves, but always settle after a little quick rev, is this a sign of something going bad?

Thanks

Glyn M Ruck

Please get hold of an OBDII scanner & read stored codes & post. The OBDII plug is under the steering column under a rectangular cover.

The car should go onto high idle at cold start to warm up the Cat's quickly.

A1EK

Yes I was planning on doing this and need to see if my OBD will work okay with this car .

This morning the car was really hard to start and took several goes as if its was chocked up, when it started the car seemed okay but obviously there is something not right. I checked the rubber breather pipe that I had mentioned early that had oil around the connections that go from the rocker cover to the throttle body actuator. I removed the throttle body and although oily inside was not too bad , the butterfly flap however did have a fair build up of gunk which I cleaned off with some spirit and I also removed and checked the MAF as I thought this could be contaminated with oil, but it was okay.

I took a photo of the breather pipe that seemed to have a lot of oily mess around it for any suggestions and in the meantime I will see if I can get the codes from the scanner.

Glyn M Ruck

That's the main captive crankcase breather pipe. Oily fumes are normal. It obviouly does not seal very well. Replacement might be an idea. You want no air leaks on that pipe or it effects the fuel trim.

A1EK

Okay i'll put a jubilee clip on both ends to see if it seals better for now.

Glyn M Ruck

A clip is a good idea if the pipe had deteriorated.

Moviela

12 years on those hoses are hard as a carp. They are cheap, and should be replaced. Clamps will not seal them because they are hard and brittle.

Your codes for the check engine lamp should provide additional clues as to the problem.

A1EK

Okay, I tightened up the rubber breather hose ontop of the crank case as it seems a little lose at the ends. I also plugged in my code scanner and as I thought it suggest the Mass Airflow Sensor I think needs replacing and the car was running rich, but perhaps someone could advise me?

Codes:
P0172 System Too Rich
P0101 Mass or Volume air flow circuit range / performance problem
P0102 Mass or Volume air flow circuit low input.

samaritrey

I would recommend new hoses as said they are cheap and you will be amazed at how flexible the new ones will be. I just replaced mine the other day and could snap all but one in half in multiple places with such minor pressure. Think of it like an 18 year old vs a 80 year old woman in bed

Carsy

Thankfully, I cannot comment on experiencing the latter.

Glyn M Ruck

If your air cleaners are clean then clean or replace the MAF. By the time these cars throw a MAF code the MAF is usually toast.

A1EK

Well took my MAF from my CLK and tried it in my wifes c class, there was no difference or in engine note even if i unplugged it whilst the car was runnung either? I ran a fault code check and it showed the same as before. Now it still could be the fact that my CLK maf is not suitable for the c class so it's not a definitive test but still worth trying.

Glyn M Ruck

Is there any damage or corrosion in the MAF plug?

mercedes4ever

Sounds like a current recall associated problem; PCV upper and lower hoses, getting blocked. PERFORM RECALL @ 2008020002 - - - VENT HOSE
025722 Replace Vent hoses 171 WM
024762 Star Diagnosis system, Connect & disconnect 171 WM
025059 Fault Memory, Read out / erase 171 WM
1 271-010-00-82-05 HOSE

All no charge.

A1EK

Many thanks guys for all your tips and advice. Please to advise all fixed now. The codes suggested the MAF was faulty as stated, so bought a second hand genuine Merc MAF on ebay for £15 , fitted it, cleared the codes with my phone and code reader, all sorted !. Ran the fault check again a few times and no faults reported !

Thanks

Glyn M Ruck

Good news. I'm pleased it's fixed.