Roudy C55

So Ive owned my C55 for around 7 months now amd no issues so far. Ive dropped over 5 grand fixing what it needed. But now recently I noticed the “Add 1qt next gas station” happen very frequently. So frequently in fact that I have to add 2qt every Day!! Which makes me so so sad knowing I love the w203. Im guessing worn piston rings but Im unsure how much that would cost. Anyone who may have done this work before let me know if I may have to sell this puppy

Robjr

Chances are it’s not your piston rings or valve leakage. More than likely, it’s your rear main seal and valve cover gasket. The valve cover gaskets are an easy fix for a DIYer. Unless you’re an experienced mechanic, I’d leave the rear main seal to the pros and an Indy repair shop with a good reputation! Good luck with diagnosing and fixing the leaks!

Rob

Viper98912

I had the following leaks on my C55:
- Rear main seal
- Valve covers
- The little cover on top of one of the valve covers
- Oil filter canister

I would check those first as they are more likely than the piston rings. Some of these may only be slightly leaking, or may be leaking like crazy

brauhaus313

You guys think he can lose 2 qts a day from the typical oil leaks m113 engines have? 2 qts a day means he would be leaking oil on the ground everywhere he drives and parks but it doesn't sound like that's the case.

OP, do you notice blue smoke in your exhaust? At a rate of 2 qts a day I'm pretty sure you'd have a substantial amount of blue smoke in your exhaust.

If you're not leaving oil everywhere you drive and park and no blue smoke, maybe you have a bad oil level sensor. Unfortunately our cars don't have dipsticks. If it were me, I'd drain the oil and measure how much you actually have in there. You could be way overfilled right now because a bad oil level sensor keeps telling you to add oil even though the oil level was right. Being far overfilled can cause it's own set of problems and cost you alot more money than you've already spent.

Thread from the W211 platform, but oil level sensor technology is basically the same and can cause the problem you have:

https://mbworld.org/forums/e-class-w...refueling.html

Spooky55

I've had 2 of these cars and they both drank oil at the alarming rate of about 1qt/300mi. Both cars smoked when hard on the throttle.

There were definite leaks at the oil cooler, valve covers, and rear main seal, but never enough to leave a spot in the driveway. Fixed all but the rear main seal. No change in consumption.

I changed the oil level sensor on my last car, thinking that must be it. Nope.

No amount of valve stem sealer, thicker oil, or additives seem to help. I haven't had a chance to borescope the cylinders or do a compression test, but the car runs great otherwise...

As far as I'm concerned, it's just a fact of life with some of them. I wish it wasn't, but I'm 2 for 2 now. I just drive it and keep a couple of quarts in the trunk for every time the warning comes on. You're not alone. I love the car otherwise and will drop another motor in it when this one either gets too bad or grenades.

insame1

I would get under the car and look. A rear main seal could be the problem. You might be one of the few that still have the belly tray and when it is parked nothing drips then when you start driving it flys out the back and gets burnt on the exhaust.

brauhaus313

The OP stated having to add 2 qtrs PER DAY. A quart every 300 miles is too much to say it's normal. A qt every thousand miles or so is within spec but on the high side. Some burn very little over 5000 miles. It's too bad he hasn't bothered to come back and reply, but even if burning a qt/300 miles, you would have to assume he's driving around 600 miles a day. Doesn't add up. To be clear, I'm not saying he's not consuming oil, but his rate of consumption isn't normal. Simple, dumb things like vacuum leaks can increase oil consumption, but that's not a normal running condition either. On that point, I'd highly recommend replacing the two round rubber gaskets in the intake tract between the MAF and throttle body elbow, and the elbow and throttle body on our older cars, especially if high mileage. There was a bulletin released probably about 15 years ago by Mercedes that these seals can go hard and cause harder to find and less obvious vacuum leaks than say a split hose, causing lower gas mileage and higher oil consumption.

PJmak

2qt a day is a leak from something broken not lack of maintenance on valve covers or rear main seal.

No way in hell you are loosing that much oil from there and you should definetly not be driving that car if that much oil is coming out.

Cracked oil pan could be an issue. I just dont know how youd not see the leak with that much oil coming out.

brauhaus313

That's why I think it could be a bad oil level sensor. There's no way 2 qts a day from a leak wouldn't make it's way onto the floor everywhere he drives and parks and be coating everything under the car. The OP hasn't bothered to come back and respond in over 2 weeks though so .

I can't find the bulletin referencing the intake tract seals I mentioned earlier, but here's a vid talking about it. The video shows changing the seals on the intake for an M112 V6, but the idea is the same for M113's. M113's have two seals as I stated prior, unless you have an E430 which only has one seal like the M112.

Sulaco

2 quarts a day would have drastic and obvious consequences on the engine's ability to burn fuel and operate. That's literally like adding several drops of oil to every single combustion chamber on every single RPM. Your plugs would foul out in 40 seconds, your engine would be shaking and misfiring violently, and your exhaust would be a cloud of blue'ish smoke so thick you can't see through it.

insame1

I think you would notice after 2 day when you are completely over full.

brauhaus313

Even with a bad oil level sensor? Would you like to elucidate how one would notice, yet not notice 2 qts leaking from a rear main seal a day as you suggest? 2 qts of oil a day leaking from the rear main seal wouldn't simply disappear by burning off on the exhaust, again, as you suggest. I think you speak from inexperience to suggest that 2 qts a day would simply just hang around in the undertray and not be noticed because it will just burn off on the exhaust.

As I stated in my initial reply, being overfilled can cause a host of big and costly problems and suggested checking his actual oil levels...but we haven't heard back from the OP yet about further symptoms, issues, or resolution.

PJmak

Buy an oil dip stick and measure manually

kjb55

Should you buy the dipstick - the C55 reading is 165 mm. Mercedes part number: 120 589 07 21 00

akuhr

Check your spark plugs. See if they are drenched in oil. I have an '05 C55 with 155K miles currently. I have been adding about 1L of oil every 500 miles (and upwards of 2L every 500 miles if doing mostly city driving) for the past 3 years. Car runs fine and have never had any major issues related to the engine or cooling system. I love the vehicle and can't imagine selling it; it just has some character haha

amgen

I recently changed these 2 plastic gaskets in the elbow, number 260 and 270 in the chart below. While at it, I changed number 20 too.



Afterwards I noticed 4-5% better fuel economy and a slightly better throttelresponse. But honestly the weather has stopped me more accurately exploring the improvements.
The new 2 plastic rings seem to be made of a slightly different material and had both several grooves on the outside for a tighter fit in comparison to the old ones.
I don´t regret changing them!
Thank you "bauhaus313" for this excellent tip!! :-)

Btw, I haven´t had any oilconsumption problems with my C55.

Roudy C55

Hey Thanks for your reply. So far i have continued to use up 2 QTs a day but it being cold right now really seems to help me out because now its only 1qt every 3 days. I have lifetime warranty on all gaskets so I replaced them but It has not fixed a thing! Car smokes Black on full throttle so its running lean. My plugs are Black after less then 2 months so Its obv something up with the Oil. I changed them out but man Can I say for how much Oil my baby burns she is a champ. Did a Quick Pull against a Turbo S2k and Beat him. Having 235k Miles on this C55 does not help either but she sure as hell looks brand new. Bought another C55 and a Cls55 Just in case anything happens with this one. Anyone Interested in one of the highest Milage C55’s that burns oil? Haha Didn’t think so. Love the input from everyone this community rocks!

LukasBMW

Mystery solved. 235,000 miles means your rings and valve seals are toast. You'll either need to rebuild your engine or deal with replacing your spark plugs every few months. And forget about ever passing emissions.

Might be a good time for a 55k swap. Prices on used 55k engines are more expensive then before Covid19, but they are still fairly reasonable.

That would be my plan of attack.

PJmak

Where are you located? I have someone who might be interested in the car

brauhaus313

235k is impressive. At that mileage the engine has served its purpose in life. However, did you ever check what your actual oil level is when your car tells you to add oil? BTW, black plugs (carbon fouling) and black smoke out of the exhaust typically indicate you are running rich, not lean. Black oily deposits (oil fouling) on the spark plugs would indicate what LukasBMW stated.

Roudy C55

Im located in the state
of maryland. My C55 has been holding up like crazy. Had my mechanic check her out and he confirmed its the valve seals. Currently considering one of two options but I need your help! Motor Runs like a champ but honestly want more power/fun with this car. Plan A, Is M113k Swap and make around 650 HP with all the mods. Plan B, is one you guys are going to hate me for… but I was thinking AWD K24 Turbo in the C55 Haha. I can fully build the motor for under 10k and have a 900+ Whp Turbo C55. Thinking about Minting out my Interior too. Anyone with Clean set of Ash Interior Interested in selling?

Roudy C55

Yes sorry Running rich is what I meant. Thank you all for the help and support. W203 community is unmatched. Checked my actual Oil and I indeed was burning 2 Quarts a day. It fluctuates depending how I drive her. Fully redid suspension and she handles like it came out the factory! New Paint Job for the Stock Alloys and Clk Bumber it bothers me having those tint rock chips.