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Ok, I have a 2013 C250 sedan with an oil leak that burns off and is big enough to need to refill a quart or less every few weeks, and puts oil stains on the driveway. It burns off and can be smelled at stoplights as well, even making a small amount of smoke at times.
Back of engine, plastic engine shroud removed, passenger side...oil sitting in a crevice (better pic below)
Oil in crevice...back rear, top plastic engine shroud remove
Closer up of puddle/oil accumulation
Oil making mess on trans and ground. Bottom engine shroud (for oil changes from below) removed.
I was thinking it was a valve cover gasket, but location made me not think so. I heard the valve cover has a built in PCV valve that can spit out oil? This is pretty much on top of the rear, right, and top of engine. Where is the oil coming from? Dipstick? There is no accumulation on the silver/metal heat shield that the plastic coolant tubes run along on that side. Any ideas? I am pretty sure someone has come across this.
Ok, I have a 2013 C250 sedan with an oil leak that burns off and is big enough to need to refill a quart or less every few weeks, and puts oil stains on the driveway. It burns off and can be smelled at stoplights as well, even making a small amount of smoke at times.
Back of engine, plastic engine shroud removed, passenger side...oil sitting in a crevice (better pic below)
Oil in crevice...back rear, top plastic engine shroud remove
Closer up of puddle/oil accumulation
Oil making mess on trans and ground. Bottom engine shroud (for oil changes from below) removed.
I was thinking it was a valve cover gasket, but location made me not think so. I heard the valve cover has a built in PCV valve that can spit out oil? This is pretty much on top of the rear, right, and top of engine. Where is the oil coming from? Dipstick? There is no accumulation on the silver/metal heat shield that the plastic coolant tubes run along on that side. Any ideas? I am pretty sure someone has come across this.
Actually I'm in the process of changing my oil filter housing which is located on the driver side. I've done so much work to my 2013 C250 coupe it's insane. I've had it in my garage now going on 3 months. I've done cam adjusters, timing chain, alternator, starter rebuild, O-rings in the turbo lines the list goes on and on. It looks like it's either the o-ring in your turbo line up in front of the passenger side and could be making it's way to the back where you see it or believe it or not my oil housing gaskets were leaking only to find a couple bolts loose and the housing was actually broken. Figured that out after replace the oil housing gasket. Total waste of time as I'm replacing everything all over again but this time the housing included.
If you can look at the turbo line that is directly in front of exhaust manifold. It's the only line there and it runs directly across the back of the wastegate. It's the one that comes out of the turbo and has a banjo bolt at that end where the turbos mounting clamp is. That turbo line is notorious for it's o-ring leaking where it's mounted into the side of the head. Another place it could be coming from is the oil housing gasket. You can't see the gasket but the oil would be dripping down directly along side the starter. I had to rebuild my starter because of that leak and replaced my alternator because of the turbo line o-ring that leaked. Hopefully that helps. Let me know how you make out or if I can offer any advice that will point you in the right direction. 👍
@Jason Cancel I am also getting ready to change the gasket on the oil filter housing.
Can you shed some insight as how you're planning to do it?
Here's a thread I just opened.
Actually I'm in the process of changing my oil filter housing which is located on the driver side. I've done so much work to my 2013 C250 coupe it's insane. I've had it in my garage now going on 3 months. I've done cam adjusters, timing chain, alternator, starter rebuild, O-rings in the turbo lines the list goes on and on. It looks like it's either the o-ring in your turbo line up in front of the passenger side and could be making it's way to the back where you see it or believe it or not my oil housing gaskets were leaking only to find a couple bolts loose and the housing was actually broken. Figured that out after replace the oil housing gasket. Total waste of time as I'm replacing everything all over again but this time the housing included.
If you can look at the turbo line that is directly in front of exhaust manifold. It's the only line there and it runs directly across the back of the wastegate. It's the one that comes out of the turbo and has a banjo bolt at that end where the turbos mounting clamp is. That turbo line is notorious for it's o-ring leaking where it's mounted into the side of the head. Another place it could be coming from is the oil housing gasket. You can't see the gasket but the oil would be dripping down directly along side the starter. I had to rebuild my starter because of that leak and replaced my alternator because of the turbo line o-ring that leaked. Hopefully that helps. Let me know how you make out or if I can offer any advice that will point you in the right direction. 👍
ok, isn't that the same turbo line banjo bolt that gets replaced with the revised, smaller inlet one? I have the kit to reduce oil in exhaust at startup. The problem is that entire heat shield that runs above it has no oil. I mean that big heat shield that the two plastic coolant lines run on top of. No oil (but stained a little with old coolant when the coolant lines leaked before replacement ;-) i think there would be oil on the heat shield if from there...all the way back to where I am accumulating oil. The place I am leaking is the passenger-side (U.S.) rear, towards battery side and next to oil dipstick, which is opposite side of the oil filter housing. Unless oil housing squirts to other side over the valve cover (and I have no stains), I am not seeing that as an option either.
ok, isn't that the same turbo line banjo bolt that gets replaced with the revised, smaller inlet one? I have the kit to reduce oil in exhaust at startup. The problem is that entire heat shield that runs above it has no oil. I mean that big heat shield that the two plastic coolant lines run on top of. No oil (but stained a little with old coolant when the coolant lines leaked before replacement ;-) i think there would be oil on the heat shield if from there...all the way back to where I am accumulating oil. The place I am leaking is the passenger-side (U.S.) rear, towards battery side and next to oil dipstick, which is opposite side of the oil filter housing. Unless oil housing squirts to other side over the valve cover (and I have no stains), I am not seeing that as an option either.
I had a leak in the exact location of your picture. Replacing the cylinder cover (valve cover) gasket corrected the problem. It could be blowback from a leaking o-ring on the turbo oil line but there are lots of parts between the cylinder head and the back of the engine where you would also see oil deposits. Oil filter housing leaks tend to drip down the driver's side of the engine onto the starter. Clean the area and swap out the cylinder cover gasket. It's simple and inexpensive.
I had a leak in the exact location of your picture. Replacing the cylinder cover (valve cover) gasket corrected the problem. It could be blowback from a leaking o-ring on the turbo oil line but there are lots of parts between the cylinder head and the back of the engine where you would also see oil deposits. Oil filter housing leaks tend to drip down the driver's side of the engine onto the starter. Clean the area and swap out the cylinder cover gasket. It's simple and inexpensive.
Cool, thanks. I was thinking someone with an almost identical problem would show up. I had also heard the oil separator (pcv-like) on the back of the engine could be it (and may cause excess blowby pressure), but I have to face it may just be the valve cover...or both. Thought of just clamping down the valve cover bolts tighter? I hear they have to be replaced anyway when changing the valve cover gasket but not sure.
I wonder if maybe this is caused by excessive blow-by pressure (as the engine ages and blowby from worn rings)..wonder if a blow-by filter engine oil cap would end it and release stress from valve cover gasket...or if this would just cause an additional engine code from unexpected pressure change ;-)??? I may try that as a quick test...as that would be a feat and cheap if it ended the problem.
Cool, thanks. I was thinking someone with an almost identical problem would show up. I had also heard the oil separator (pcv-like) on the back of the engine could be it (and may cause excess blowby pressure), but I have to face it may just be the valve cover...or both. Thought of just clamping down the valve cover bolts tighter? I hear they have to be replaced anyway when changing the valve cover gasket but not sure.
I wonder if maybe this is caused by excessive blow-by pressure (as the engine ages and blowby from worn rings)..wonder if a blow-by filter engine oil cap would end it and release stress from valve cover gasket...or if this would just cause an additional engine code from unexpected pressure change ;-)??? I may try that as a quick test...as that would be a feat and cheap if it ended the problem.
When I removed the cover, the rubber gasket was brittle rather than flexible, probably the result of age and repeated heat cycles. The cylinder head cover itself is part of the PCV system, and it forms an air-tight seal against the cylinder head. It's important that the bolts are tightened in the correct sequence and to the correct torque (9 Nm for the cover boils, 8 Nm for the coil bolts) to create this air-tight seal and ensure that the cover is not warped. I wouldn't add a blow-by-filter engine oil cap or over-tighten the bolts. Start to finish, you can swap out the gasket in under an hour, and the cost of the parts is less than $50 with MB parts.
Here’s a good video. The only thing I don’t like is that he used a power tool to run the coil bolts back in prior to torquing. You may already have the tools but FYI: A light torque wrench is needed but it doesn’t have to be digital. Small beam or click wrenches are inexpensive. The job takes 1-1½ hours including prep and clean-up.
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