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  • 02-25-2011, 03:25 PM

    Re: Questions

    You are close to being able to see and touch the oil separator, although removing it is a whole different story. If you remove the driver side upper timing cover, the oil separator is behind and beside the chain guides. From there you could see well enough to know if the plastic hose on your separator has failed, and you could rig it with high temp rubber hose if necessary.

    You would of course need a new gasket for the upper timing cover.

  • 02-25-2011, 01:41 PM

    The oil separator is behind the front chain >>


    One symptom of worn/broken chain guides inserts is plastic bits in the oil pan.

    Visit realoem for illustrations of the crankcase vent system.

    Consider finding a well-regarded BMW indie, often superior to, and cheaper than, the dealer. If you have Consumer's Checkbook in your region, join and look at their shop ratings.

    If not,
    Ed in San Jose. BMW CCA member since 1987 (Nr. 62319). Golden Gate Chapter. '97 540i 6 speed. Build Date 3/97. Aspensilber over Aubergine leather.
  • 02-25-2011, 11:31 AM


    I'm in the middle of replacing my CCV and valve cover gaskets. I have the intake manifold and valve cover gaskets off right now. How far am I from the oil separater (how much more work is there to get to it)? Do you have any pics or illustrations of the parts that need to be replaced? I'm going to the dealer tonight for a couple of hoses and the part that connects the throttle body to the intake manifold (I broke the nipple on that thing).

    How do you know you need timing guides? My '00 540i6 has 155k miles. I'm pretty sure my car needs just about everything. I still have the original clutch. Replacing that will be a job for the dealer.

  • 02-25-2011, 10:58 AM

    540i oil separator tip (behind the chain guide)

    This is for those whose rear intake manifold covers (CCVs) keep clogging up with oil.

    Since I'm having to replace my timing guides anyway, I'll be swapping out the oil separator for a new one, but... there is a fix for those that don't need to pull their timing guide rails. The part of the oil separator that fails is the bit of (ridiculously brittle) plastic hose which connects the main body of the separator to the outlet (which accepts the pipe that runs underneath the intake manifold to the rear manifold cover). The outlet is held in place by a small bolt on the center guide rail, and if the plastic hose is already damaged, it will come right out when that bolt is loosened. The rest of that plastic hose is very easy to knock off, and can be replaced with appropriately-sized high temp rubber hose from an auto parts store. It's a bit difficult to get in there, and I ended up having to grind down the hose, both on the outside and a bit on the inside edges to get the hose to slide over the nipple on the main body of the separator. You won't be able to clamp it, but assuming the hose is sized right, there's no way for it to come off, because it is a very short length running between two parts that are jammed in place.

    I'll post a pic of the old separator as fixed next to the new part once I have it out of the car this weekend. Although it's a pain, it's not nearly as bad as pulling the timing rails and the lower timing cover. And I suspect the rubber hose could outlast the plastic hose by a wide margin.

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