The lower cap on my 2002 Jetta TDI -- the one that retains the oil cooler unit onto the bottom of the filter housing (or so I infer from looking at a (borrowed) exploded drawing) -- has a hex nut head molded into its end, to facilitate removal.
Does anyone know what size socket will fit?
At initial oil change since purchase, I used a Vise-Grip to remove the cap. Very gingerly, as it's plastic.
I'd like to use a socket, but no one locally can tell me what size to use (my attempts to measure it brought back caliper readings from 32.8mm to 34.2mm -- poor access, miserable visibility, the technique of a tyro).
Not even the dealer knows. When I questioned their service section directly, they gave me a blank look and said, "We never remove that. We remove the oil filter unit top cap before pulling the pan plug, and it all drains just fine."
I've only changed the oil once since purchase, but my (non-engineer) impression was that the bottom cap had to come off. Otherwise, some oil would remain no matter what removal sequence I followed.
I searched tdiclub.com's FAQ and articles sections, and such items are not addressed.