Oil sending unit

[72bumbee]

Got a new oil pressure sending unit to install, is this just a remove and replace item, or should I know something to do this? When things look too simple, and inexpensive, I like to ask.

[knightfire83]

Yup, a simple replacement, like changing a light bulb.

[72bumbee]

thanks sir!

[basketcase0302]

You don't want to put teflon tape on the threads tough, (I put the stuff on about everything).
The threads of the sending unit give it a "ground".

[72bumbee]

Would you believe it came out of the box with teflon tape already on it??

[robroy]

Hi 72BumBee! Did it come with tape over 100% of the threads, or only over a portion of them?

I've noticed that several oil pressure sending units I bought came with tape on them too, but it was only covering about 1/3 or 1/2 of the threads. I guess they're thinking that the remaining, exposed threads will be an OK ground, while the tape over a portion of the threads helps to seal in the oil.

Robroy

[70_F100]

You don't want to put teflon tape on the threads tough, (I put the stuff on about everything).
The threads of the sending unit give it a "ground".

There is enough contact between the threads, even with teflon tape, to provide a good ground if the tape is used properly.

However, I haven't used teflon tape in years, because oil and gas cause it to break down.

I use Loctite PST on all NPT fittings.

[robroy]

Good afternoon! I followed 70_F100's great advice before and used this stuff on my oil pressure sending unit.



Here's a photo of my water temperature sending unit installed with this stuff.



And the oil pressure sending unit with the stuff applied.



Unfortunately I never got to try any of these sending units out before pulling them apart again! But I liked working with that fluid better than the tape. The tape's kind of difficult in comparison, and I've heard that strands of it can break off and get pulled in to the engine.

Robroy

[Supermike]

If you look at the Motorcraft one O'Reilly sells, it comes pre-coated with something...

http://www.oreillyauto.com/site/c/detai ... nding+unit

I've never understood how those work.

[knightfire83]

It's just a variable resistor operated by a lever that moves between a spring and a small diaphragm against the engines oil PSI.

The gauge is supplied with regulated (+) voltage on one side, and the sending unit is the variable ground to complete the circuit.

Same operation as a fuel sender, just allot smaller. http://auto.howstuffworks.com/fuel-gauge1.htm

The insides of an oil sending unit: http://www.allfordmustangs.com/forums/a ... sender.jpg

[Supermike]

Thanks, knightfire... good info!

[dustman_stx]

Got a new oil pressure sending unit to install, is this just a remove and replace item, or should I know something to do this? When things look too simple, and inexpensive, I like to ask.

Be aware there are 2 different types of sending units. One has a small hole and the other a larger hole. One is for the gauge setup with a warning light, the other for the actual gauge type setup. You should've been asked when you bought it if it has a light or gauge.

[72bumbee]

OMG... That thread sealant is expensive. Too rich for my blood!!! Just took the old one out and screwed the new one in. Watch that needle move. I love it when stuff works. Thank you again guys for all the great pointers.
Steve