Oil pressure sending unit leaks

I swapped my old 302 on my 68 standard to a 1993 5.0 HO this past winter. I reused my old sending unit and after a week of driving it started to leak. I replaced it with Standard Parts #PS149 based on my 68 spec. and everything appeared fine until last night when I discovered another puddle of oil underneath my car. It was now leaking too. Note that it wasn’t coming from either connection but the unit instead. So last night I decided instead to go with Motorcraft part number
SW-2178-A based on 93 5.0 instead. Well it’s installed but now the light remains on. Anyone have any ideas or suggestions as to what’s going on?

You need to be using a OP sending unit that is compatible with the car, not the engine. The correct one for a 1968 Cougar with idiot lights is this one: OP switch

My real concern was why did my original and then the correct replacement start leaking oil. Just coincidence or is there something more going on. I have to remove both A/C and P/S belts, loosen and swing up the P/S pump, remove the oil filter and remove the inside bolt on the fuel pump and loosen the other so it drops slightly down, all to be able to remove the sending unit.

Probably leaking because of an installation error.

Royce, with all due respect I think they were installed correctly. Maybe I didn’t make myself clear. The units themselves are weeping oil out their housings. All the threaded connections were dry.

I think it’s just bad luck. Sounds like the extension tube is maybe missing. I’m not sure that was used on all Cougars maybe just XR7

1 Like

I have the extension tube. I never removed the sender from it when I transferred it from one block to the next.
I did switch from conventional oil to full synthetic and I thought that might have been the cause but when the second one (new) started doing the same thing I wondered.

If you still have the original just clean the threads thoroughly and put some Permatex #2 on them and screw it in snug. Pipe threads can be ruined by overtightening.