Cad. 390 oil pressure sending unit location?

Tom Hoczyk

PCS Past President
Can anyone please tell me EXACTLY where on the Cadillac 390 engine (my '60 Eureka) the oil pressure SENDING UNIT for the idiot light is located? I gave it a cursory look today, even under the car, and it didn't jump out at me. Many thanks in advance! Tom hoczyk@yahoo.com
 
sending unit light

I had a 60 48'' miller. it just had a red warning light that came on. By that time, it's too late most of the time. If it gets hot, just turn off ignition and pull
over
 
I am relying on my memory, and I believe that in the 1960 engine, it is located on the left (driver) side of the engine, low on the left side, toward the front, on the side of the engine block. Check between the first and second spark plug area. I believe that later on, sometime between 1962 - 1964 it was relocated to the rear of the engine block behind the intake manifold, just left of center. Easy way to check the switch is to turn the key on, and the low oil pressure warning light should illuminate. Then start the engine and it should go out.
Paul
 
where is my sending unit

Tom,
I will be home on Sunday and can look for the placement of the sending unit for you. We are in Indianapolis for a dulcimer festival now.
Hope you can wait another day.
Mike
 
It's on top of the block just behind the valley cover, adjacent to the distributor.

Several Delco numbers will work: 1508434, 1997884, 1998113, 3632326, 3632488. Or, Cole Hersee 8601.

Light will switch off at 6-10 PSI.
 
Thank you all for your information. Just so that you know, I'm asking because I want to install an actual gauge in the car, so as not to rely on the idiot light, for the exact reason Kent mentions. I already have a volt meter installed, and want to fill the 2nd hole in the plate. Tom
 
if you like the rest of us the only place you can put the gage is were you can't read it. do your self a favor and put in a pipe t and use the gage and the light. that way if something happens the light will let you know a lot faster then the gage you not looking at.
 
where is

Tom,
I see Kevin and several others have given you the answer to where is your oil sending switch. We just got home. I looked in my 61 Cadillac shop manual and the switch is beside the distributor. I don't know when the change was made so a 60 may still be down lower on the block by the oil filter. Now you can let us know where when you find it.
Mike
 
The location is the same from the first OHV 331 through the 365/390. It moved with the introduction of the 429. I put a tee on my 50 Superior as well. It came with a gauge and I added a light because driving the car required so much physical effort that I didn't always watch the gauges.
 
was out doing some stuff today and checked the 63 the sending unit is here on it.
 

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I do believe that all of them are 1/8 pipe thread. haven't seen any different ones. back there a close nible and a t are all you would need
 
a tee and

I installed a tee fitting and then reinstalled my sending unit. Then I ran the hose for the gage. The hose kit was long enough that I could run the hose through the firewall hooks for the other wires and hoses that Cadillac and
M-M used. My idiot light still works but I pay more attention to the gage.
Mike

:my2cents:
 
I installed a tee fitting and then reinstalled my sending unit. Then I ran the hose for the gage. The hose kit was long enough that I could run the hose through the firewall hooks for the other wires and hoses that Cadillac and
M-M used. My idiot light still works but I pay more attention to the gage.
Mike

Mike if it is a kit with the nylon line for the gauge? If so I would replace the nylon with 1/8 copper line the first chance you get. :my2cents:
 
nylon or copper

Daniel,
That sounds like a strong recommendation on the oil line. Guess we will do it when we get the new exhaust and header gaskets in. I know there must be a horror story to go with your advice. So we don't aquire one of our own we will heed advice.
Thanks,
Mike
 
Switch location update

Yesterday, using a stack of towels and 2 foam pads, I was able to crawl on top of my engine to see that the sending unit is where Ed (and others) said it would be, adjacent to the distributor, basically beneath the vacuum advance, down below the level of the intake manifold, difficult to see under all circumstances. I used a miniature Rigid pipe wrench to try to remove it, and it wouldn't budge, despite my best efforts. I really wasn't able to get much leverage on it at all. Every position was clumsy.

It appears that the best way to remove it would involve pulling the distributor and the steel engine vent tubing. The sending unit does not have flats on it, but is more rounded, with little vertical slots around it, perhaps to accommodate a special socket tool.

It's not a pressing project. I may do more work on it before PCS Hudson, but it has moved way down the list, since I have lots of chrome to polish. Thank you, everyone, for all your help! Tom
 
rounded oil sending unit

Tom,
Oil sending units are more rounded. You may be able to borrow a special socket from your parts store when you get the new unit. Most parts stores (here anyway) loan the tools to do a job. They can probably sell you one of the sockets too. It is one of those tools that will lay in the tool box for a long time before you need it again.
Mike
 
Tom, I wish we lived closer, I'd happily loan you my oil pressure sending unit socket. The sender has a 1/4" NPT thread. I would definitely use the plastic tube kit from Stewart Warner. Copper work hardens and will eventually crack next to the ferrule nut. I'll never make that mistake again.
 
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