I'm fitting an aftermarket 52mm Oil Pressur Gauge, and it came shippd with a sensor. The sensor should after the manual just slot-in from where the previous pressure sensor should be. The Engine is a 1990 B230F so the sensor is located to the right of the oil filter. It is really a painstaking effort on even to get it out, not to mention trying to get the new sensor in. (It is thicker at the back, round and where you can use spanner is thin. Only 13mm. and the round thick back is approx 5cm. The brand of the gauge and sensor is Equus. Hope somebody can help. Can take pictures if you want to.