dgdrx

2001 e320 4x 276k miles new car to me; im simple weekend car guy,not much experience but can handle routine maint items. Noticed driver valve cover has another cover on top that is narrow and extends across valve cover, also contains the oil filler assembly. Seems to be leaking and I see
a little gasket just peeking out. What is this piece called, looks pretty simple to remove and replace gasket; also looks like oil filler "neck" might be leaking at its base where it connects the cover I described on top of valve cover. The car needs a tune and I will attempt the valve cover gaskets, plugs and wires. While doing this work anything else make sense
to swap out? I've seen chat about a chain tensioner; I believe my motor has never been apart/worked on. Thanks

RichardM98

If you haven't done so, you might want to read through the stickies to see what issues might be a potential problem.

As for valve covers which are a common leak area, they are two parts as you mentioned. There is a MB gasket for the cover/cylinder head seal but not for the upper/lower valve cover halves. After disassembly and cleaning use a bead of RTV to make a seal. The last time I checked the OEM gasket was not available unless you purchase the entire valve cover assembly.

Why do you think the plugs and wires need replacement? FYI - you should get a special spark plug boot removal tool (Hazet 2771 or equal) to avoid damage the wires if you are replacing the plugs.

Some service to consider -

Brake fluid flush (DOT 4+) - every two years
Coolant flush - every three years

O2 Sensors - every 100K or when you get a code

If tensioner is not making any sounds, it's probably OK for now.

Another leak area is on the front of the engine just down and to the left of the oil filter. A rectangular cover about !"x1 3/4" with a round plug. This is the oil inspection port. Small rect. gasket.

dgdrx

Thanks for your help. The upper cover includes the plastic oil filler column
and you say there is no manufactured gasket; upon inspection I can see a seal so it must be gasket sealer you describe. I purchased R and L valve cover gaskets from rocky mountain autoparts; Im assuming for the driver side lower valve cover and the left valve cover? I have service records that
indicate the plugs have near 90k miles so I was going to replace them. I did follow one thread that highly suggested replacing the wires at the same time because of the high miles. I will replace brake fluid and antifreeze soon. The car is very clean and was well maintained. I will need the front end looked at as the ride is a bit slushy and the tires have worn
badly to the outside in the 2k miles I have driven. I'll have this checked out when I get new tires in a few weeks.

RichardM98

The oil fill tube has a gasket at it's base. Just a round flat fiber 'washer'.

Just to clarify - As I understand it, the car comes from the factory with a gasket between the two halves of the valve cover. But since it doesn't have a part no. it can't be ordered. However, if you purchase an entire valve cover assembly (ie both halves) there is a gasket installed. I was told that even at the dealership a sealant is used to seal the two halves if a leak develops. Beware that the tubes from the ERG valve to those covers become brittle over time.

The plug wires are pretty robust so I haven't heard of too many failing. Also, a set is pretty expensive.

Feel free to ask questions. There are plenty of W210 DIYers. There are even sites with pictures/video of common maintenance procedures.