Oil pressure sending unit: tool for easier removal and replacement

[Ace]

Oil pressure sensor leakage is not unusual on an older vehicle. If a significant sensor leak starts up suddenly you can lose a lot of oil quickly. If you don't see the low oil light, or an oil pressure gauge, you could quickly have a ruined engine. A replacement sensor is relatively inexpensive ($5.29 for mine from AutoZone).

I recently replaced my oil pressure sending unit (for idiot light) because it was suddenly leaking oil profusely. I swung the alternator all the way over to the left side to provide access to the sending unit. It would have been an easier job if I had had the right socket. I managed with a large crescent wrench but it was awkward because of cramped space to attach and turn the wrench.

Removal and replacement of the oil pressure sensor on a Tercel 3AC engine is best done with a special 1-1/16" (27mm) six-point socket as shown in photo. The space is too cramped to work a socket with attached rachet unless you remove the alternator mounting bracket from the engine. A short socket with a hex end to take an open end wrench will expedite the job.

Note that an ordinary 12-point socket risks stripping out.

[NWMO]

Ace,

Pretty easy access and while the socket is ideal, I’ve always been able to get a wrench or pliers on the sending unit and remove it pretty easily.

Chris

[Ace]

This subject became a big deal to me because one day my oil light flashed on while I was driving around town and I discovered the engine oil was below the dipstick. The oil had been near the full mark about 250 miles previous. The loss was due to a suddenly leaking oil sender.

I found it somewhat inconvenient to wrench on the oil sender because of projections on the engine block and the protruding coolant drain plug, see photos. The alternator bracket obstructs use of a socket and rachet. It would have been an easier task with a regular 1-1/16" (27mm) open-end wrench but I was away from home and improvised with a bulky crescent wrench. I would have bought the special socket if it had been locally available for cheap; I was concerned about possibly breaking the small threaded neck of the sender by tightening it with the wrench at an oblique angle.

[NWMO]

I understand. Mine is a little easier to get to now, I installed a tee so I could pull a line for an oil pressure gauge as well and just moved the op sensor out.

Chris

[Ace]

Yes, excellent idea to also have an oil pressure gauge. I should add one myself. I think it would also be a good idea to have an audible warning buzzer for low oil pressure that occurs when the engine is running, to protect against rare (?) events like I had.