On 2000 XJ I-6, 4.0L
Anyone tried to loosen the coolant system engine block drain plug on the driver side of the engine, exactly below the intake manifold.
it is a pain, looks like it can be reached with an extension, the plug is a square fit, don't know if there is a tool fits there and what size, I appreciate you all help.
The early plugs are an 8m/m square drive, which is also just about the same as 5/16". A tool may be readily made from a 5/16" or 8m/m hex key, using only a grinder, and done in about five minutes. (Had to do this for my BA-10/5 transmissions. It's easy.)
Later plugs may take a 3/8" square drive, simplifying the process.
I am unsure if they used a standard tapered pipe thread for this - if they did, it's probably 3/8"NPT or 1/2"NPT, and a replacement plug may be gotten at any hardware store. I'd recommend brass for a replacement - it won't seize.
I'm considering putting a small, cable-operated valve in that port when I overhaul my engine, to simplify thorough drainage of the coolant. Pulling the lower hose doesn't get all of it, you'll have some crud left. Even pulling the plug doesn't get all
of it, but it will get a lot more.