Does anyone know what the thread size is on the oil sending unit, I would like to have it before I take it out and hook up the gauge.
My sender is going bad, is says no pressure then full pressure, I checked the connection already.
92 Superduty 7.3

 

Um... they only put oil pressure /switches/ in the more modern 7.3s. It's not going bad, it's how it was designed. It may be hooked up to a gauge in the dash, but it's actually a switch -- it's what they did in my '88 F250.
If you want to replace it with a sender, it's possible, but you also have to remove a loading resistor they put inline(either on the wiring harness on the right side of the engine, or on the back of the instrument cluster) so that they could use the gauge with a switch-type sender. Do some searching, it's easy to find.

That being said, it should be a 1/4NPT, IIRC(either that or 1/8" NPT, but I think it's 1/4"). Even if you do replace the sender, though, it won't be very useful as our gauges aren't that accurate anyway! I did this, replaced with a stock sender and removed the resistor, and while it worked, it was inaccurate enough to tell me about nothing.

I would go on Ebay and buy a nice, digital gauge+sender from China. They're about $25, and work extremely well - I'm quite happy with mine, being able to see it change as I change speed. The stock gauge is very slow, at best.

 

Um, guess I wasn't clear enough.
I know it's not a true gauge that's in the dash, but it does show if there is pressure I just wanted to know what the thread size was on the sending unit (SWITCH!!!) before I took it out to install a gauge in the cab.
And yes it is bad, sometimes it works and sometimes it doesn't, not a connection problem.
I don't intend to try and hook up the SWITCH to the new gauge, just want to know what the fitting is before I take it out to install the fitting for the gauge line in case I have to have an adapter.
I'm trying to save trips to the parts store, I live in the boonies.
It was a simple question.

 

I think it is 1/8"NPT

 

Hmm, this RockAuto listing: More Information for STANDARD MOTOR PRODUCTS PS240 hints that it's 1/4" NPT. I'd say get both adapters, then return the one you don't use, next trip to town....

 

It's 1/4" NPT

 

Thanks Guys.

 

Watts 1/4 in. x 1/8 in. Brass MIP x FIP Hex Bushing-A-738 at The Home Depot