Modern vehicles take in and relay a lot of information, mostly via electronic signals and sensors. Back in the old days, oil pressure gauges were connected to the engine using a hollow tube tapped into one of the oil galleries. Pressurized oil would come up through the tube, and push the needle on the gauge. However, it didn't take long for auto engineers to figure out that allowing high-pressure, flammable hydrocarbons into the passenger compartment -- among lots of electrical devices -- wasn't a great idea. The oil pressure sending unit solved that problem.
Raise the hood of the vehicle. Raise and support the vehicle on jack stands.
Remove the electrical connector from the oil pressure sending unit. The unit will be very close to the oil filter. On older cars, the sender will be a small, round unit about 1 1/2 inches in width. On later models, it will still be round but will have a black, 1 1/2-inch-long cylinder extending out with a two-wire connector. Just squeeze the connector and pull it straight out.
Loosen the sending unit with a deep-well socket or a wrench, whichever fits. Unscrew the sending unit the rest of the way by hand.
Wrap some Teflon tape around the threads of the new sending unit to prevent any possibility of leaks. Screw the sending unit in as far as possible by hand, followed by tightening with the same tool used in its removal. The important thing here is to tighten this sending unit until it is good and snug. It should never be overtightened because it will break at the threads very easily.
Install the electrical connector by matching up the connector with the sending unit and pushing it on until it clicks into place.
