Oil Pressure Sending Unit

My oil gauge is pinned....im thinking its my Oil Pressure Sending Unit...

If I unscrew the Oil Pressure Sending Unit, is it going to shoot oil all over the place....or does this need to be done during an oil change? I see where it unscrews from, but i'm just afraid to get it off, and have something horrible occur and not be able to get it back on. Thanks...

No problem - there's no pressure behind it when the engine is off. You can do it during an oil change if you really want to, but it's not necessary.

If you feel the need to use a sealant on the threads, make sure to use RTV Copper, and only put it on a thread or two. The sensor is self-grounding, which means that metal-to-metal contact is REQUIRED for it to work properly. Teflon paste has about a 50/50 shot at smearing away enough to work - but RTV Copper hasn't failed me yet. Go lightly with the stuff.

Prepare the new sensor, and have it in your other hand when you're pulling the old one. Like I said, there's no pressure - but there's no sense in losing too much oil due to gravity...

5-90

If you are not sure it is the sending unit try tapping on it they will usually come back to life for a while.As stated it wont leak a whole lot when removed without presure.bought 89 wag. from dealer who thought rod bearings were bad i.e. knock. turned out to be o.p. sending unit and bad harmonic balencer.

5-90 said:

If you feel the need to use a sealant on the threads, make sure to use RTV Copper, and only put it on a thread or two. The sensor is self-grounding, which means that metal-to-metal contact is REQUIRED for it to work properly. Teflon paste has about a 50/50 shot at smearing away enough to work - but RTV Copper hasn't failed me yet. Go lightly with the stuff.


5-90

Click to expand...

Guess I should take the teflon tape off mine and see if the SOB actually works. :eyes: :shhh:

Well, I just took a trek out to see if I could find a replacement unit. Stopped first at Napa ($40 somethin bucks!?), then to advance auto ($25), and asked to look at the unit. I then realized that I have an Instrument Cluster (dash) from a upgraded Jeep that has the gauges. The OPSU I looked at has 2 pins inside of it, but the one I have now only has one. I wasn't 100% sure if I bought it that it would work with the gauges. Is this necessary to get a read-out on a gauge'd dash? I think the one pin connection is only for the light oriented dashes. Thanks...

Not entirely true - the RENIX gage sender has a single connection. At least, the four that I've got do...

The sensor may also have changed externally - but will be the same internally. The sender for the light has a switch inside that is pressure-activated, and the one for the gage will have a variable resistance unit inside.

However, you will need to make sure that you get the one-pole if that's what you've got - it would be a huge pain to have to run an additional ground somewhere, that makes for another wire to keep track of, and it's a lot of work for little return.

Yes, I've noted that these typically cost $35-40 to replace in the aftermarket, so that's not too outlandish...

5-90

I just had the same problem last week with the pegged oil guage. I looked up the part online at AutoZone. The part that comes up is "NIEHOFF OP24731", $9.99. I checked out Niehoff's web site and it lists the other applications for this part. I thought it looked familiar, as it is the same as the sensor I removed from my '87 Camaro 2.8L engine when I upgraded the gauges. Since I never throw anything away...I was able to use the sensor in my Laredo with the 4.0L. Now the gauge is working normal again. Also,no oil came out when I removed the bad sensor, but the car had also not been driven for a whole day. Hope this helps.

OPSU for guage cluster is usually < $20 online.

http://www.morris4x4center.com/cherokee/menu.htm

A couple of years ago I replaced the sending unit in my 96.
I used teflon tape on the upper half of the threads and it worked.
One thing I remember is that it has an odd wrench size and I had to buy a special socket from O'Reilly's, wasn't expensive.
Now I am waiting for another sending unit to go bad so I can get my money's worth out of the tool

That's funny - I usually just use slip-joint pliers. Don't bear down on them, and you'll get the sensor in and out just fine.

I've got the socket from years ago (when I was doing a lot of them...) but it's a shorty for the "light" sender, rather than the "gage" (which usually wants a deep socket.)

Teflon tape worked for you because you didn't coat ALL the threads with it - that's the key. You've got to preserve metal-to-metal contact, or your sensor won't ground enough to work...

5-90

krizgawd said:

My oil gauge is pinned....im thinking its my Oil Pressure Sending Unit...

If I unscrew the Oil Pressure Sending Unit, is it going to shoot oil all over the place....or does this need to be done during an oil change? I see where it unscrews from, but i'm just afraid to get it off, and have something horrible occur and not be able to get it back on. Thanks...

Click to expand...

You can remove the sending unit without any problem. As long as the engine's switched off, there'll be no oil pressure so at worst you'll lose a few drops of oil. Just put an old rag underneath to soak them up so you don't stain the ground.
The new sending unit will already have thread sealer on the thread so you don't need to add RTV copper, teflon tape, or anything else. All you need is a 27mm open wrench (or an adjustable) to tighten it up but be careful not to overtighten it.