First you need get under and see what type of drain plug you have and how much interference you have from other parts of your car's frame and crossmember. My '60 Fintail has a bolt-head drain plug - very easy to reach with a regular 19 MM box-end wrench. My pair of W114 '72 250s (250 sedan & 250 coupe) have the same drain hole but the coupe has the bolt type plug while the sedan needs a 14 MM hex-bit (like a large allen wrench) Both 250 drains are close to the subframe crossmember. I can get a wrench on the coupe but a regular allen wrench won't fit on the sedan so I had to get the special allen wrench from Mercedes.

Yes, it's a large drain hole. You need to figure the least messy option - deep/wide drain pan, a piece of cardboard to catch oil spatters, etc - whatever works for you. It's really not that big a deal once you've done it the first time.

The oil filter is a canister type with a replaceable filter cartridge inside, not a spin-on like most modern cars. It's down low on the rear drivers side of the engine block so you'll need to get under there to catch the drips while you change it. You unbolt the canister from the filter mount and remove the filter cartidge. Make sure the 2 small rubber seals are there - one on the filter mount and one on the bottom of the canister. Make sure you get a new sealing 'O' ring for the canister rim (those usually come with the new filter cartridge but occasionally not!) There should also be a metal sealing washer where the long bolt goes through the canister.

Import parts stores should have an OE type MANN or Knecht filter carteridge, otherwise Fram and Purolator make replacements but not all autoparts stores may have them in stock. Make sure the small rubber seals, 'O' ring and sealing washer are in place when you reassemble the filter cartridge and canister.

Happy Motoring, Mark

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DrDKW