C55 Oil Consumption

[poppopbangbang]

Newbie here, seeking some advice on where to start looking for the cause of very high oil consumption on a C55. My CLK55 uses around a litre every 2000 miles but it has done a LOT of miles and not had an easy life. In comparison the newly acquired C55 appears to have been positively pampered but is getting through a litre every 750 miles or so. Both cars on 5W/40 Petronas.

No visible leak that would account for this level of oil loss so it must be burning it, there is no smoke on startup or full throttle but then I guess the cats are scrubbing it. Aside from the obvious elephant in the room of piston rings is there anything common (breather issues etc.) which might cause this?

Performance is good, fuel economy is good at 22MPG in mixed use, no CELs or similar. All in all it seems very happy..... aside from wanting half a litre every time I fuel it!

If it turns out it does need rings is there anyone recommended for serious engine work on these?

All help gratefully recieved.

 

[StuartK]

My Indy says don't use Petronius in amg Mobil 1 only!

 

[poppopbangbang]

My Indy says don't use Petronius in amg Mobil 1 only!

We have an oil lab where I work so no concerns over using Petronas in them having OA'd new and used back to back. Regardless it would chew through just as much of anything that was in there as this is way too much oil consumption to be oil make up or additive pack related. I really hope it's just breather system that has gone to pot somewhere so the crankcase is pressurising but suspect it's going to need to come apart for rings or an engine swap as these are alusil

 

[AMGeed]

My Indy says don't use Petronius in amg Mobil 1 only!

Funny as that's what my indy does use
If its good enough for the Mercedes F1 cars.....................

 

[StuartK]

Funny as that's what my indy does use
If its good enough for the Mercedes F1 cars.....................

I don't know much about oil but mine has always had Mobil 1 so assumed same is best

 

[AMGeed]

I don't know much about oil but mine has always had Mobil 1 so assumed same is best

Me neither. I've been using Petronas for a year now and I've topped up with 1ltr in 4.5k miles which is acceptable to me.

 

[m2287]

Funny as that's what my indy does use
If its good enough for the Mercedes F1 cars.....................

Mercedes do say to use mobil1 in the AMG engines!

 

[StuartK]

Funny as that's what my indy does use
If its good enough for the Mercedes F1 cars.....................

My check at next fill up was coming up loads. Turned out the litre I was putting in was not filling it to top dipstick mark. Now I've dine that it's been off for ages.

 

[Will]

It's not this one is it?

http://www.mbclub.co.uk/forums/classifieds-cars-sale/199955-2004-mercedes-benz-c55-amg.html

 

[poppopbangbang]

It's not this one is it?

http://www.mbclub.co.uk/forums/classifieds-cars-sale/199955-2004-mercedes-benz-c55-amg.html

No not that one, this one's black and was a late night ebay purchase as a part ex to clear. It was cheap so don't mind sticking a couple of grand into sorting it if required as it's in very good nick everywhere else and was sufficently under priced to still be worth what it's cost when sorted.

 

[Lenny63]

get a leak down test done?

 

[Mrhanky]

Mercedes say 1 litre every 800 miles is within spec. I have seen 55's use very little oil and seen some use about the above.

I would check for leaks, rocker cover and breathers are an easy place to start.

 

[poppopbangbang]

So apparent solution (if anyone is interested) to this. The main breather which runs off the back of the LHS rocker cover had collapsed internally on its way to the throttle body and the rubber gasket between throttle body and elbow wasn't in the greatest of condition.

Using a -500- +500mbar mechanical gauge I took a crankcase pressure reading from the dipstick tube and on blipping the throttle was seeing around 90mbar crank case pressure. Which either means totally knackered motor or no breathers! Interestingly there doesn't appear to be any PCV system on the M113 engine.....

Replaceing this breather hose along with cleaning and flushing the two smaller breathers and resealing the leaking throttle/breather seal resulted in a crank case pressure reading at idle of -4mbar and on blip a reading of similar - zero.

Having just done 60 miles in it according to the dash it has used no oil and certainly feels a bit sharper.

Will update if this has solved it once a few more miles are on the clock!

 

[Mrhanky]

So apparent solution (if anyone is interested) to this. The main breather which runs off the back of the LHS rocker cover had collapsed internally on its way to the throttle body and the rubber gasket between throttle body and elbow wasn't in the greatest of condition.

Using a -500- +500mbar mechanical gauge I took a crankcase pressure reading from the dipstick tube and on blipping the throttle was seeing around 90mbar crank case pressure. Which either means totally knackered motor or no breathers! Interestingly there doesn't appear to be any PCV system on the M113 engine.....

Replaceing this breather hose along with cleaning and flushing the two smaller breathers and resealing the leaking throttle/breather seal resulted in a crank case pressure reading at idle of -4mbar and on blip a reading of similar - zero.

Having just done 60 miles in it according to the dash it has used no oil and certainly feels a bit sharper.

Will update if this has solved it once a few more miles are on the clock!

Nicely done mate, hope it's that simple for you.

 

[merc85]

I think PCS as adivsed this on a previous thread, Well done Sir looks like you have found the solution

 

[Lenny63]

Great work

 

[ThirstyC55]

Any chance of a long term update? Experiencing a very similar issue. I've tried to PM you but it appears your box is closed (or we are both too new.)

 

[Petrol Pete]

Hi Thirsty from New York. How much oil is yours burning through ?