Hello,
Thank you all for your help, this forum is a godsend. I recently purchased an 85' 300TD wagon with 285k on the clock. I had to make a hasty decision to buy the car because the guy was leaving the next day. After test driving, I was sure it was an injector nailing beacuse the car had great power, blows no smoke, and had great oil pressure. I was surely wrong! After removing the fuel lines one by one (no change) I removed the injectors and glow plugs (prechambers intact) Next I removed the vacuum pump. I did notice a small scarring on the ramp the piston rides on (see pic) but all the bearings in the pump are intact. I did notice a random part hanging out under the hood and I kept it just in case(I didn't even know if it was a car part) turns out it was one of those valve things in the vacuum pump but it's not missing any. This would lead me to believe the pump had previously failed. The car had good vacuum no issues that I know of. How hard is the spring supposed to be on the VP? I cant budge that damn thing. I brought the car to a Mercedes specialist and he thought it was something(a nut or bolt) lodged in the #3 cylinder and the only way to find out would be to pull the head. $1500 to maybe, maybe NOT find the problem! Needless to say, that didn't happen. I pulled off the bottom oil pan and it was suprisingly clean just 2 tiny metal shavings and a rubber grommet or O-ring (any idea where the rubber came from??) the screen was clean but the rubber pickup boot had a tear(see pic) I'm assuming the oil level goes above this right? So that's where I'm at now, stuck with no "smoking gun". I have read Konstans thread and believe we have a very similar problem but I don't have a garage unfortunately, or the time to pulll my engine. Any suggestions are hugely appreciated. Thanks-Art

Video of the sound with air cleaner removed. FYI-The noise does not change whether it's hot or cold / idle or high rpm's.
http://www.youtube.com/watch?v=GDE9QITjteg

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