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Quick question please. I'm going to go ahead and replace my PCV system as preventative maintenance, but I'm not sure how this oil separator comes off the valve cover. I removed the bolts that hold it in place but I didn't want to FORCE it off if there was something else that needed to be done to remove it. Do I just "tap" it off since it seems to be "stuck" in the valve cover even though all screws are removed??
I replaced or cleaned most of the PCV system last winter. I wasn't sure if this was pointless or not, but the parts were cheap and I figured why not when I was doing a ton of other work. This part came right off for me. Nothing is holding it there other than 3 screws. Tap lightly on the side, or gently pry underneath if it is stuck. But you'll need very little force to get it off.
Quick question please. I'm going to go ahead and replace my PCV system as preventative maintenance, but I'm not sure how this oil separator comes off the valve cover. I removed the bolts that hold it in place but I didn't want to FORCE it off if there was something else that needed to be done to remove it. Do I just "tap" it off since it seems to be "stuck" in the valve cover even though all screws are removed??
Thanks in advance!
I am seeking info on how to replace this same PCV valve on my 2013 S550 M278 engine. Do you know where its located and how to replace it? I asked FCP Euro for the part and the one they linked to loos the same as the one you posted here.
Not familiar with the M278 engine but if its anything like the covers on the M272/273 there are no moving parts inside it to wear. Just a bunch of fins that catch the oil vapors.
I don't even see anything like this on my 2013 M278 so I'm wondering if FCP Euro led me to the wrong part. My interest was replacing the PCV valve on my 2013 s550 as its recommended to replace every 60,000 miles and my car has 100,000 now. There is oil seeping from the valve cover bolt heads on passenger side and the dealership wants $5000 to reseal them but I am wondering if its being caused by a bad PCV valve.
I don't even see anything like this on my 2013 M278 so I'm wondering if FCP Euro led me to the wrong part. My interest was replacing the PCV valve on my 2013 s550 as its recommended to replace every 60,000 miles and my car has 100,000 now. There is oil seeping from the valve cover bolt heads on passenger side and the dealership wants $5000 to reseal them but I am wondering if its being caused by a bad PCV valve.
Oil seeping is from bad-from-the-factory sealant. Common on M27* engines.
Thats referred to as the full load (wide open throttle) crankcase breather cover which houses the oil drip pan. Its not actually a pan its a centrifuge.
if you reach back and feel/see oil dripping from the cover then replace it.
I don't even see anything like this on my 2013 M278 so I'm wondering if FCP Euro led me to the wrong part. My interest was replacing the PCV valve on my 2013 s550 as its recommended to replace every 60,000 miles and my car has 100,000 now. There is oil seeping from the valve cover bolt heads on passenger side and the dealership wants $5000 to reseal them but I am wondering if its being caused by a bad PCV valve.
Sounds like the breather cover is the least of the problems. If oil is seeping from the valve crankshaft covers it might also be leaking from other areas and if severe means the whole engine needs to come out.
Either get a refurbished engine from a reputable source or prepare to fork out $$ ( unsure if you have insurance in any regards) because once the engine is out there will be few things to attend to, a pandora box.
Not much oil to be seen anywhere on this engine, its pretty clean all the way around and pretty sound, just a little oil seep around some bolt heads holding the valve cover on. Dealer gave me a quote of $5000 to reseal both sides but also said the car can be driven for years without doing it. It just smells bad after driving is all; smell of burnt oil is not pleasant.
I was merely wondering if the PCV valve was bad and causing the seep. I cleaned it off and then it reappeared about 6 months later but its not a lot and the car doesn't use any oil aside of what the manual says it will use after 1000 miles. I saw a video on YouTube about a list of things you can do as preventive maintenance to get 300,000 miles out of your Mercedes and the PCV valve was one of them. It said if its not working as it should, there would be pressure building up which causes oil to leak through seals. So I was only wondering if it was something I could replace myself but if its on the back of this engine, I think I'll pass because it would be done by feel only as I cannot see back there. That cover in the image is not leaking anything, the only oil on the outside of this engine is the little bits of seep around a few valve cover bolts. Those bolts are tight.
Last edited by s550hollywood; Dec 12, 2025 at 01:43 PM.
Reason: add something
In my opinion there is a big difference between seeping and leaking. Even the MB manual says trans fluid seeping is normal. Its the leaks you need to address.
If the pcv drip pan or covers were "bad" you would see oil leaking from the cover gasket or you would have oil collecting in the hoses past the covers.
I just noticed the oil drip pan is the same part# for the M272 and M278.
I had replaced the drip pan and the cover on my m272 as part of preventative maintenance. I had noticed a little bit of oil in the breather hose on the passenger side leading to the throttle body. My concern is the inside of the intake manifold getting all gummed up.
Not much oil to be seen anywhere on this engine, its pretty clean all the way around and pretty sound, just a little oil seep around some bolt heads holding the valve cover on. Dealer gave me a quote of $5000 to reseal both sides but also said the car can be driven for years without doing it. It just smells bad after driving is all; smell of burnt oil is not pleasant.
I was merely wondering if the PCV valve was bad and causing the seep. I cleaned it off and then it reappeared about 6 months later but its not a lot and the car doesn't use any oil aside of what the manual says it will use after 1000 miles. I saw a video on YouTube about a list of things you can do as preventive maintenance to get 300,000 miles out of your Mercedes and the PCV valve was one of them. It said if its not working as it should, there would be pressure building up which causes oil to leak through seals. So I was only wondering if it was something I could replace myself but if its on the back of this engine, I think I'll pass because it would be done by feel only as I cannot see back there. That cover in the image is not leaking anything, the only oil on the outside of this engine is the little bits of seep around a few valve cover bolts. Those bolts are tight.
If the smell is objectionable spend a couple of evenings with microfiber cloths and engine cleaner to remove it. Or pay a detailing shop to clean it up. Both scenarios will cost less than $5,000.
When exactly are you smelling burnt oil, every time you drive, after a long drive, right away, after an hour?
If the gasket on the back of the passenger head was leaking you would probably smell burnt oil as it would drip down onto the hot exhaust. Since you really cant see back there use a paper towel and feel around.
Photo below the red circle is where oil would be dripping down onto the exhaust below it. Green circle hose goes directly into the intake manifold to be burned off in the engine.
Drive side cover hose leads directly into the air manifold that leads to the turbo. I believe its the same on the passenger side.
Do you see smoke coming from the turbos? Could be a leaking oil line. I know very little about turbos.
The oil I smell is after driving the car for a while because its on hot metal around some screw heads holding the valve covers on and along the manifold. I've cleaned it off before and the smell was gone but it eventually came back after a while. Heres the same engine I found a pic of on ebay, circled in red is where I see oil on and around screw heads beneath that black rubber shield. This metal gets very hot when I drive the car, so its just heating the oil and I smell it. If I wash it off again, the smell is gone for a while but I dont want to keep washing it because Im afraid I'll get something wet that shouldn't be wet. Its just a slow seep coming from around the screws holding the valve cover on. They're not loose so my guess as well as the dealers service director is the valve covers need to be resealed. I tend to agree, but If I can find the cars PCV valve and its less than $300 I would like to replace it but I don't know where it is. I don't think its ever been replaced and I have 101,000 miles on it.
This is a picture I found of the same engine, as you can see the oil on that heat shield, well mine is doing the same but also on mine the oil is coming out from the screw heads I circled in red.
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