Super cool MB oil filter design!

I stuck a new oil filter in Katie on Saturday. (Katie is a car, by the way. ) I was very impressed by Mercedes Benz's design. I'd been told that MB provided a factory bypass filter on the diesel engine, but I couldn't find it. When I changed the one I COULD find, though, I realized that they cleverly made a combination full-flow/bypass filter in one cartridge!

The filter is a simply cylindrical unit, similar to an A4 TDIs filter. Approximately the bottom 1/3 is just a pleated paper full-flow element. But the rest of the filter is covered with sheet metal, with dozens of very small holes poked in it. Through the holes I could see densely packed fiberglass (or cotton, or something) filter material. Apparently the upper part of the filter is the bypass part! The two parts are separated by two o-rings on the center "stalk" attached to the filter housing cover. And the really cool part is that the filter elements are dirt cheap!

Hurray for Mercedes Benz! Every time I tinker with the car I notice some other simple yet effective engineering marvel. (Like the engine oil cooler integrated into the radiator. Or the big alloy cooling fins on the differential cover. Etc, etc...)

-mickey

My '84 Isuzu had a factory bypass oil filter that was to be changed every other oil & filter change. All that was available at that time was a genuine Isuzu filter. The whopping $20.00 filter was a lot of money back then.

Ric

Mickey,

Check out the engine lubrication section in the repair manual. It has excellent pictures and description on how the oil filter works.

Next time you drop a new oil filter in, take a close look at the oil return pipe (what you referred to as the center "stalk" attached to the filter housing cover).

Located on the oil return pipe about an inch from the top of the filter housing lid is the oil return hole for the bypass section of the oil filter. It's very easy to miss, it's about the size of a #5 pencil lead. That should give you an idea how slowly the oil is filtered through the bypass section of the oil filter.

To prevent unfiltered oil from splashing back up the oil return pipe there is a tiny check valve located in the bottom of the oil return pipe. And don't forget to change those two little O-rings on the bottom of the oil return pipe every few years, they get hard and brittle.

It's like you said, the more you poke around the more you are impressed with all the little engineering details.

Brian, 97 Passat TDI, 85 MB 300D-T

Mercedes engineering is truly an art form. No doubt.

I particularily like the removal handle, they think of everything.

Sounds exactly like the oil filter on my my old MB 240D.
Was a fun and solid car, if a bit under-powered.
I didn't have the heart to sell it when I moved away, so I gave it to a friend who had expressed interest in it as a piece of good automotive engineering. It went to a good home...

Mercedes came up with the "fleece" oil filter material, I think in the 1990's.

TM