Oil Pressure Switch/Sending Unit with only one prong?

[Steve Wood]

yep, I could find no difference...a ll the pressure senders seem to be 240 ohm and the threads are the same...

[SuperSix]

What about getting a PN off of the old unit?

[gordyzx9r]

Doesn't help they have two web sites:

SW does aviation, automotive, and marine.  The problem I ran into a few years ago when my tachometer was failing (because of a intermittently failing after market ignition module) was that it was difficult to get tech support because they got rid of it and outsourced it to their vendors; and forgot to tell their vendors that they did that.  It was kinda funny, I was on the phone with a woman and she was trying to help me and said I needed to call SW tech support...I said I did and that they and their website listed her name, email, and phone number on their website to contact for tech support.  I finally got a lead sales manager, and he sent me two brand new 8K tachometers and a 10K tachometer for free plus put me into contact with one of their company engineers...wh o couldn't figure it out either. 

From what my builder says, there is no PN on the old unit.  I still have the instructions from Performance Instruments and it doesn't list the part in the inventory other than saying "new oil switch/sending unit". 

[Steve Wood]

as they seem to be spec'd the same, I see no reason either will not work....SW does not seem to have but one resistance range for their pressure gauges

[gordyzx9r]

What kind of sealant should be put on the threads?  I thought I've read none, or to avoid anything teflon...

[1KWIKSIX]

What kind of sealant should be put on the threads?  I thought I've read none, or to avoid anything teflon...

 
I did not use any sealer on my brass VDO temp sensor or my VDO Oil pressure sensor.
 
With the one wire set up, the sensor needs to ground for them to work properly. If teflon or sealer is used, I read that they will not ground and will not give proper read out.
 
These are NPT (National Pipe Taper) threads, so they will seal themselves when tightened snugly.
 
I've had mine installed for several years now, no leaks!
 
dave

[SuperSix]

You need SOME sealant - I used liquid teflon pipe sealant. a THIN smear in the threads.

The stock replacement OEM pressure sender I just installed had some on the threads from the factory..

[Steve Wood]

liquid teflon is the usual suggestion from the manufacturer

[daveismissing]

I think the teflon is more about getting it back out again....

[SuperSix]

I don't think so. It's to create a more seal-able surface on the fittings. Fills in/seals small imperfections in the threads, fittings, etc.

[Charlief1]

I don't think so. It's to create a more seal-able surface on the fittings. Fills in/seals small imperfections in the threads, fittings, etc.

Mark's right here. The only other way to get a perfect fit is to lap the parts in and it''s much easier to use a sealant of some sort. A lot less messy as well.

[daveismissing]

We have water pumps that we fire up and prime each spring. the steel plugs we pull always seal
-sealant or not. But you sure are pissed in the spring  if you didn't get some tape on the plug
 the last time in the fall.

[gordyzx9r]

For some reason the gauge reads worse than it did before with the old sending unit.  Other than getting a new gauge, is there a way to isolate the problem?  The oil pressure reads fine when using a mechanical gauge under the hood but it's way off with the electrical gauge.

[daveismissing]

IF the mfg published a resistance vs pressure chart you could put known resistors in place of the sender and check the gauge, or measure the resistance of the sender at various pressures.
I've not seen one tho.

[Steve Wood]

Damn...SW gives you the min resistance and the max resistance with appropriate temps as well as stating to use Teflon liquid so the  single terminal sensor will ground properly.


The GM manual gives you the resistance and temperatures as well.


You need to get out more!