When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I had a bad camshaft sensor (exhaust side) leading to a stable yellow check engine light with a slightly rough engine and a temporary vibration after each cold start. Bought a new one and took my car to an MB mechanic. He took off the engine cover to replace the sensor. I noticed what looked like old oil with dust stuck to it on the driver's side. I also noticed the same around the oil fill cap. He said it's probably the head cover needs fresh silicone. He said MB cars don't have a head gasket. Instead, they're sealed using silicone. The oil dipstick showed a normal oil level after around 8k miles since the last change, and the car runs great after swapping the bad sensor. No more rough engine, and there's no burning smell or funny noises. No exhaust smoke either.
Oh one more thing: I had bad fuel pump and relays a few months ago that an indy replaced. He initially replaced the fuel pump but the car kept shutting off when it gets hot until he figured out it needed new fuel relays. I don't know if that has anything to do with the oil/fluid traces on the top area of my engine. But I thought I'd add it for clarity. My car now has 125k miles on the odo.
I attached a few photos. What do you think? Is this an oil leak? What's the suggested fix? Also, what do you make of the oil residue around the oil fill cap?
Last edited by klingsor; Feb 12, 2022 at 09:21 PM.
no sign of a leak, just a very mild weep once upon a time...
there is at least 3 litres of spare oil in there - if you never drive above 100mph for extended periods
in Germany they do 4k rpm and 130mph for hour upon hour - the 8 litres are to help out under those circumstances
Are you suggesting that it was a discrete incident? What could have caused it? I'm suspecting the bad camshaft sensor might have been the culprit as I left it unfixed for three months and drove the car about 2k miles with the bad sensor. I also suspect the old mechanic who fixed my fuel pump a few months ago. They might have spilled either fuel or oil (I can't tell what this nasty dirt is).
Anyway, I'm taking her in for another issue (to replace the coolant water pump and thermostat as well as a broken coolant hose that's causing a slow coolant drip which has been causing coolant loss of about 1/2 liter every 6 months or so). My mechanic is suggesting that I get the head resealed. I'll have him clean everything and inspect it again after a few days to see if there's anything else needs fixing.
I really love the car. I haven't had any major complaints in the nine years I've owned it aside from expensive three fuel pumps, one radiator, and really expensive suspension parts. I'll try to keep her alive until I put my hands on the EQS, hopefully this year.
the early cars ate the camchain and sprockets and the cam sensors not only leaked they didn't work either
its an old car now, if you had a leak you'd have a puddle to worry about - a few recent post about cam sensors and oil coolers leaking check them out....
I just wanted to post an update for future readers:
My man found the source of the leaks. The big mess on the driver's side was caused by a bad camshaft position sensor that failed on me three months ago causing a CEL to go off. I replaced that one a couple weeks ago and the CEL went away. He found two other camshaft position sensors on the passenger's side that are failing but not quite there yet to throw a CEL code. I told him to replace all three sensors as I figured they're bound to fail so I might as well take care of it now. He also applied sealant on the front cover as he said it's likely to cause a leak in the near future.
Unrelated to this issue: I've been having a recurring issue with the coolant level. A message on the dash indicating I should top off the coolant that would appear every two/three months when I'm taking curves on highways. I'd add about 300ml (10oz) of coolant to top it up every time until the message would reappear two/three months later. He found the coolant water pump failing, two pulleys that are also failing, and a top and a bottom coolant hose that are dripping from the joint rings. He replaced the water pump, all the hoses plus the thermostat housing and a bunch of gaskets and sealing rings.
He said he was very worried when he saw the pulleys' condition as if they had seized on me while driving, they would have caused the belt to snap and cause a lot of damage that would have certainly taken out the radiator plus a bunch of stuff. I'm kind of glad I was concerned about the oil leaks to find out about the failing cooling system before it destroyed my engine.
The engine looks much better. If maintained in that condition or better any problems, such as leaks, can be found and addressed before they become serious.
Looks good. Also looks like your airbox is cracked right at the elbow.
I've checked the engine compartment a couple of times since the fixes as the technician told me to make sure there are no more leaks. Found none, and the oil and coolant levels are per spec. Your comment made me go back and check again. Apparently it's not a crack. I don't know what it is but it looks like a line of hardened glue.
After replacing the four camshaft position sensors I find my car to drive noticeably smoother. I thought my car drove OK before the sensors swap but now I know it wasn't a good baseline.
This morning I spilled cappuccino on the central console area. Wiped it clean immediately but not fast enough. My hazard lights button died but not the other neighboring buttons. Went to my mechanic. He removed the central console cover and found milk/coffee residue on the board. He said the entire board needs replacing. Called a couple of junkyards but they only have pre facelift W221s. I think I'll shell out the $ for a new one.
Edit: misspelling.
Last edited by klingsor; Feb 23, 2022 at 06:01 PM.
Is that towards the front of the block? If so, front cam covers. Just had my indy do mine two weeks ago! There’s no actually gasket, so a sealant is applied.
Are you suggesting that it was a discrete incident? What could have caused it? I'm suspecting the bad camshaft sensor might have been the culprit as I left it unfixed for three months and drove the car about 2k miles with the bad sensor. I also suspect the old mechanic who fixed my fuel pump a few months ago. They might have spilled either fuel or oil (I can't tell what this nasty dirt is).
Anyway, I'm taking her in for another issue (to replace the coolant water pump and thermostat as well as a broken coolant hose that's causing a slow coolant drip which has been causing coolant loss of about 1/2 liter every 6 months or so). My mechanic is suggesting that I get the head resealed. I'll have him clean everything and inspect it again after a few days to see if there's anything else needs fixing.
I really love the car. I haven't had any major complaints in the nine years I've owned it aside from expensive three fuel pumps, one radiator, and really expensive suspension parts. I'll try to keep her alive until I put my hands on the EQS, hopefully this year.
I bought an EQS 580 three days ago...pretty cool car. But I still love the analog feel of my 2008.
no sign of a leak, just a very mild weep once upon a time...
there is at least 3 litres of spare oil in there - if you never drive above 100mph for extended periods
in Germany they do 4k rpm and 130mph for hour upon hour - the 8 litres are to help out under those circumstances
I've not heard this before...are you saying the engine carries way more oil than needed under typical/non Autobahn driving? I'll worry less if I ever find the engine a little low on oil, if so.
I found a coating of old oil on my oil cooler a few days ago...anyone know if this is typical, or perhaps the gasket is starting to fail? Since it is right above the newly installed belts and pulleys, I'd hate to have new oil dripping on those.
Last edited by nath_h; Feb 16, 2023 at 03:35 AM.
Reason: addition
Is that towards the front of the block? If so, front cam covers. Just had my indy do mine two weeks ago! There’s no actually gasket, so a sealant is applied.
Mine got diagnosed with the same issue yesterday. Getting it fixed at my indy on monday. $1140.00 to have it done. '14 C300 (M276) 60k miles on the odo.
This is an adjacent issue to the original post, but thought I'd add here rather than a new string. I changed the oil yesterday--a few days short of 1 year, and about 7000 miles. I don't recall used engine oil looking so bubbly and orange in color rather than black. Anyone have a guess what, if anything, is up? Coolant tank looks clean. Used oil was Mobil 1 0w-40.
oil isn't meant to come out black - whilst it is designed to keep the gunk trapped in the oil - if the emission control and the vehicle use is correct, then these days on petrol cars the oil may well come out looking clean - in the old days overly rich fueling and cheap oils often gave it a harder time
the bubbles are probably just that it was very hot and as its such thin junk it takes little to make it aerate - when pumped around to bits that matter it shouldn't have the bubbles that you created as it hit the catch tray as a thin drip doing a 10" drop
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.
