any type of coolant to use specifically? suggestions?

links on how to clean oil bath filter? thanks

On an iron motor with iron head, it probably doesn't matter.

I still use the Mercedes Benz coolant ($18-25/gal) from the dealer or Zerex G05 ($13/gal) which is what the later cars need.

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68 280SL - 70 280SL - 70 300SEL 3.5 - 72 350SL - 72 280SEL 4.5 - 72 220 - 72 220D - 73 450SL - 84 230GE - 87 200TD - 90 190E 2.0 - 03 G500

Nissan GTR - Nissan Skyline GTS25T - Toyota GTFour - Rover Mini - Toyota Land Cruiser HJ60 - Cadillac Eldorado - BMW E30 - BMW 135i

I was going to say the exact same thing. Even though a well-respected shop near me said I could use any standard green coolant, I still use Zerex G05.

Regarding the air filter, just remove the filter element and use diesel fuel or gasoline to clean it. You really need a solvent basin to do it right. They warn you not to use water because it may make the wire wool rust inside it. Remove all the old oil from the bottom of the filter holder, and clean that up as well. Fill to the line with any motor oil, and then put the filter back in. Easy peasy (but very messy).

One thing I still don't understand is are you supposed to pre-coat the filter with any oil prior to installation? The FSM clearly says to add oil to the holder and then install filter element, so I don't think you need to coat the filter. But I had an old can of WD-40 which was barely spraying, so I decided to spray my filter with it prior to installation. I know WD40 isn't good for much, but this seems like a reasonable application.

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1968 220D, w115, /8, OM615, Automatic transmission.
My 1987 300TD wagon was sold and my 2003 W210 E320 wagon was totaled (sheds tear).