<!-- from fixya rte -->How to change oil sending unit - 2002 GMC Envoy

Oil sending units are normally by the oil filter housing. If i had a year make model and engine size I could tell you exactly

first need to buy oil pressure sending unit 3/8 deep socket remove oil pressure sending unit you need teflon tap sealer for oil sending unit threads.okay to replace oil pressure sending unit.you need safe raise support vechicle locate oil pressure sending unit next to the oil filter.disconnect oil pressure sending unit wire connector then use oil pressure sending unit 3/8 socket remove the sending unit.then take new oil pressure sending unit use teflon tape white plumbers tape or use thread sealer apply to the oil pressure sending unit threads then install new oil pressure sending unit and reconnect electrical connector to sending unit.then crank engine check for oil leak if all is good lower vechicle back to ground wait several minutes check engine oil level.you good to roll.

Click on link to view.http://www.autozone.com/autozone/repairinfo/repairguide/repairGuideContent.jsp?fromSearchPage=true&pageId=0996b43f80cb42b6&partName=Oil+Pressure+Sensor&partId=0996b43f80cb42b6

remove sending unit and install mechanical gauge to see oil pressure psi if psi reads ok- change sending unit again if psi to low less then 6 replace oil pump och.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/mike_9693b5ad75773352

either replace oil sending unit or get a manual oil pressure gauge and screw in to oil sending unit port and visually check with engine running to see if or what the actual pressure is. If 0 pressure registers then bad oil pump. but if good pressure, then you have a bad oil sending unit. also change oil filter.

IF OIL SENDING UNIT LEAKING OIL NEED REPLACING.WHEN INSTALLING NEW OIL SENDING UNIT.YOU CAN USE TEFLON PLUMBERS TAPE ON OIL SENDING UNIT THREADS BESURE WHEN INSTALLING NEW OIL SENDING UNIT.PUT TEFLON TAPE JUST A LITTLE ABOVE THE BOTTOM THREADS. SO YOUR OIL SENDING UNIT THREADS GET A GOOD GROUND FROM ENGINE BLOCK.SO IT WILL WORK CORRECTLY.

In order to troubleshoot this problem correctly,you need to clean the motor first.

An intermittent/shorting oil sending unit is the source of the problem.

You need to make sure it's not an oil leak into the oil sending unit first.


After you clean the motor then look for oil leak.


Also make sure the wire from the oil sending unit wire is not touching the engine block.


Oil sending unit is cheap. It's an easy job.


Change it at your next oil change.

The oil pressure sending unit is located behind the oil filter, Threaded into an aluminunm housing. It has wiring that plugs into the sending unit. The oil filter has to be removed and you will need a deep well socket and a 6 inch extension. Change the oil and the sending unit together.

With the tranny flush, yes. It's possible that they may have knocked the connection loose or broke it at the sending unit. The unit is usually located on the side near the bottom ot the tranny. With the oil change I'm going to say no. The oil sending unit is generally located on the driver side, center of the engine block near or under the exhaust manifold, or on the front of the block towards the top. Unless they moved them on me, it shouldn't be anywhere close to the drain plug on the oil pan, and there no way that they should get near the oil sending unit when changing the oil, unless the sending unit is near the oil filter, and GMC generally doesn't put the two near each other for this reason. Just thought of something. Are the gages individually replaceable, or are they all built into one display unit?

they sell some kind of special socket at the autoparts for oil sending units