Fluctuating oil gauge

1991 CHEVROLET VAN
191,000 MILES • 3.5L • AUTOMATIC
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KIMBERLEY WENGER
  • MEMBER
  • 2 POSTS
My oil gauge bobs from mid to high and ultimately buries to the high side. but my van runs perfectly. At idle (in park) the gauge stays still in the middle.
May 20, 2020 at 5:52 PM
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JACOBANDNICKOLAS
  • ASE Certified Mechanic
  • 110,194 POSTS
  • ASE Certified Mechanic
Hi,

It sounds like the oil pressure switch may be going bad. We have two choices. First, replace it and see what happens, or get a mechanical oil gauge at a parts store and see if it has the same results. Most parts stores will lend you one. Basically, you remove the electric oil pressure switch and install the mechanical. There is an oil pressure relief valve, but that usually isn't the case. However, take a look through this link. It explains how fix a high pressure issue.

https://www.2carpros.com/articles/high-oil-pressure

I can help you locate the oil pressure switch and explain what to do, but I need to know if this is a full size van and I need the correct engine size.

Let me know.

Joe
May 20, 2020 at 7:00 PM
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KIMBERLEY WENGER
  • MEMBER
  • 2 POSTS
Thank you Joe. It has a 350 engine. The oil pressure sending unit?
Kimberley
May 20, 2020 at 7:31 PM
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DANNY L
  • ASE Certified Mechanic
  • 5,648 POSTS
  • ASE Certified Mechanic
Hello, I'm Danny.

As Joe stated you can possibly rent a mechanical gauge at your local auto parts stores and test the oil PSI by putting in place of the oil sending unit. It is located at the top rear of the engine block near the ignition distributor. I've attached pictures below of what it looks like and its location.Hope this helps and thanks again for using 2CarPros.
May 20, 2020 at 8:32 PM
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