Spark plugs and rocker box gasket oil leak

[Dizz]

2005 3.2 CLK
Car is idling a bit lumpy this morning although seems to drive okay I’m wondering if oil is getting onto a spark plug as I have an oil leak from the Rocker box
Do I need to remove the spark plugs to change this gasket.
Is this a DIY job I know the spark plugs can seize up and be a problem.
Thanks.


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[clk320x]

Rocker cover gasket leaks on 99% of those M112s and almost never causes an issue tbh

 

[Dizz]

Hi mate
Left hand side coil packs look wet’ish with oil and one spark plug lead too.
I’m sure this is causing the lumpy idle.


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[clk320x]

Hi mate
Left hand side coil packs look wet’ish with oil and one spark plug lead too.
I’m sure this is causing the lumpy idle.


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Ah okay mate - here’s a guide (shows a m113k) but similar process
How to – Change Rocker Cover gaskets and reseal breather covers on the M113/M112 engine | FotiFixes.com – A Journal of my fixes

 

[Dizz]

Thanks for the link.
Blimey that seem like a lot of work!
Too cold and wet for me to do on the driveway.
Going to have to ring the garage I think.


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[pcthrillrider]

2005 3.2 CLK
Car is idling a bit lumpy this morning although seems to drive okay I’m wondering if oil is getting onto a spark plug as I have an oil leak from the Rocker box
Do I need to remove the spark plugs to change this gasket.
Is this a DIY job I know the spark plugs can seize up and be a problem.
Thanks.


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it's not the rocker covers it will the crankcase breather covers gaskit they are rtv sealant common problem on m112 i did mine both sides big job

 

[amazighman]

Not a hard job,
You can replace the breather valve and hoses while your there.
Preferably use genuine rocker cover gaskets.... I used febi ones before and it leaked no matter what... Genuine one was good

 

[55AMGCLK]

Hey Dizz

I assume you have had the car scanned by a diag machine and nothing is showing up?

Rough idling can be caused by a number of issues including a vacuum leak, throttle body etc etc.

As clk330x mentioned, rocker cover leaks are quite common and do not necessarily cause any issues.

 

[Dizz]

Hey Dizz

I assume you have had the car scanned by a diag machine and nothing is showing up?

Rough idling can be caused by a number of issues including a vacuum leak, throttle body etc etc.

As clk330x mentioned, rocker cover leaks are quite common and do not necessarily cause any issues.

Not had a scan yet as this only started happening yesterday, will get it booked into someone ASAP


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[Petrol Pete]

Dizz, I looked into doing mine some time back, despite being pretty 'handy' with a spanner or two I decided to pay my indi to do it, at least that way if it leaked it would be his problem . I can't say exactly what he charged because I had the plugs changed and other stuff done at the same time.

Not a nice job to do outdoors either, especially in this weather.

 

[Dizz]

Cars running fine again now but I’ve booked it in to an Independent Mercedes garage (Tm Motors) to investigate what’s going on.


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[Dizz]

Update it’s fixed! £460
They were actually two issues going on here both unrelated.

1. Oil leaks
Oil filter housing/ cooler seal
Both crank case-covers and associated breather pipes.
2. Rough idle
Broken bracket holding pipe from air mass sensor causing a gap and allowing unmetered air in.

No STAR codes other than relating to the misfire/idle

Fit bracket and reconnect hose....instant perfect idle etc
New breather pipes, reseal crankcase covers, clean up excess oil and all is good again.
Interestingly the mechanic mentioned that the crankcase covers had been resealed before, but in his opinion it was quite poorly done.

So thanks to you all for your replies, some of you were spot-on with your diagnosis and advice and also thanks to ‘TM motors’ ( independent Mercedes garage) in Molesey Surrey, first time I’ve used this company and would recommend them to anyone who needs some work done on their Mercedes

 

[Petrol Pete]

Result . Money well spent.....better if they never leaked, but it is what it is.