Oil Pressure Sending Unit

[tucsonjwt]

The oil pressure gauge on my 83 C20 454 has been reading high (~45 lbs) so I went looking for the sending unit and I think I found it above the oil pan on the driver's side toward the front of the engine. So, I have a few questions.

1. Is what I have in the photo actually the oil pressure sending unit?

2. There are only a couple strands of wire left attached to the unit, so is it possible to get deeper into the sending unit to splice into the wires coming out of it or are the wires sealed to the unit?

3. If I do replace the sending unit, will I lose any oil or can I replace the unit with the crankcase full of oil? Any tips for replacing that unit? It seems like there is only one single wire going to it - so is it grounded off the engine block?

Thanks

[mongocanfly]

Yep...that's it..
Not sure what you mean by splicing into wire coming out of it...it should have a terminal stud that the wiring harness plugs onto..
Wire attaches here...

[tucsonjwt]

Thanks for the information. I don't understand the threaded plug on the end shown in your picture and how it would involve an electrical plug. I don't see a blade for an electrical connection in your pic, and don't understand the mating threaded connection. Is there a piece I am missing?

[mongocanfly]

Ring terminal with a nut

[tucsonjwt]

Thanks. I got it now. I think I will try to carefully remove what is left of the wire and see if I can liberate that ring terminal without damaging the end of the sender. There appears to be a rubber boot on the end of the sender, so maybe I will find a ring terminal under that.

[mongocanfly]

Rubber boot would be common to protect threads and terminal...

[Dead Parrot]

Not sure on this one, but have seen similar setups work like spark plug wires. The wire connector simply is pressed on the end and held in place by spring pressure.

Also, the engine does serve as the ground for the sender current.

Sender probably has a little oil in it that will spill out when removed.

I would fix the electrical connections first before replacing the sender. Might get lucky and the problem is bad connections.

[Wgesnerjr]

just replaced mine two weeks ago and it had a spade connector. the wiring harness had a plug with a boot on it like the OP pic.

[tucsonjwt]

My sending unit has a male spade type end for a 12 ga female quick connect. I replaced the wire up to the harness on the top of the engine with a 12 ga wire but I still have high oil pressure (maybe higher now ~ 48 lbs.) So, I will order a new sender and see what happens.

The original wire coming off the harness looked to be only about 18 ga, and the insulation was very hard from the desert heat + the big block engine heat. I had a very difficult time stripping off the insulation without shredding the wire, but I was able to get it soldered to a new 12 ga wire and put it inside a 1/4" wire loom.

I hope the new sender works or I guess the gauge is the only thing left to replace.

[Wgesnerjr]

Exactly like mine. I put mine in a year or so ago during the LS swap. It just quit two weeks ago. Quick replacement and I'm up and running again. Hope it lasts longer this time.

[tucsonjwt]

I have read elsewhere that a high pressure oil pump can cause these sending units to fail prematurely. I am surprised that an LS engine would use this old school one wire sender. I had to look around to get one of the AC Delco senders. Rock Auto had none - I am getting one from Summit, along with a side mount temp sender connector and lead to go with my new coolant temp sender which is reading too low. Oil pressure too high - coolant temp too low - between the two I should average out OK.