just a quick question does this sensor just pull out or unscrew or do u have to twist it in a certain position fanks

Release the horseshoe-shaped plastic retaining clip by pulling it straight out from the closed end, then the sensor pulls out of the housing. The "O" ring tends to stick in the housing and needs to be fished out with a small right-angled screwdriver. Assemble with a new "O" ring.

Black sensors should be replaced with green ones - good pattern spares are available from GSF.

rotodiesel.