fluctuating oil pressure gauge

[Underdog]

I was returning from a trip tonight when I noticed my oil

pressure dropping off. The gauge eventually climbed back

to near normal but, continued to slowly fluctuate the rest of the way home. There was no smoke,no strange noises no

obvious oil leakage. I suspect the sending unit may be

going bad. I'll take a better look in the morning when it's a

little warmer. Has anyone had this problem? Can anyone

offer suggestions as to what I should check for?

 

[Philip]

Our pressure switches are a dual purpose switch. There are two functions inbeded into them. The first function is to keep the low oil light on untill there is oil pressure. To test this function.



Unhook the sending unit wires. Then with the engine off. Measure the resistance between the switch terminal and the metal housing of the switch body. The reading should be 0 ohm's. Start the engine now. If the switch is working properly there should be no ohm reading with oil pressure.



To test the pressure side of the switch.



measure the resistance between the sending unit terminal and the metal body of the housing agin. The reading should be open. No ohm reading on the meter. Start the engine now. The ohm meter should read between 30 to 55 ohms depending on the engine speed,oil temp, and the oil viscosity.



If the previous results are not obtained, replace the switch.



To tell which terminal is which. When the harness plug is unhooked. With the locking tab on the switch on top facing up. the sending unit terminal is on the right hand side. The oil light switch terminal will be on the left side.



If you have a manual gage. I would also do a temp hook up to see what the pressure is for real. Then fix the factory gage.

 

[Philip]

Here is a very crude drawing of the switch terminal position when looking at the switch with the harness plug removed.



Go ahead and laugh at the drawing. I was never known for drawing skills.

 

[Underdog]

Philip,



Thanks for the info. I'll drive into town tomorrow and see if

I can locate a ohmeter then, I'll try to check out the switch.

 

[Evan A. Beck]

Looks like a pre-schooler drew that diagram. *LOL*

 

[BushWakr - RIP]

:-laf :-laf :-laf Philip, buddy, yer killing me here :-laf :-laf :-laf



Heck of an effort though...



Peanut gallery bob

 

[Philip]

Peanut gallery bob

LOL



What do you expect from about one minute in paint shop. LOL