Oil pressure and oil pressure switch

mgm1986

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Hey folks, looking to learn a bit about what others have been doing for a quality oil pressure switch. I replaced it at the beginning of the season and at some point over the last few weeks it stopped closing, keeping the light off at all times. This was a Standard Motor Product switch.

I replaced the failed switch with a TRQ switch which failed after just a few trips, easily less than a hundred miles. This switch failed opening so the light would not go off. Upon further inspection it actually "popped the top" and was leaking oil which explains why it wouldn't close.

Confused I decided to check the oil pressure.

I run 15w-40 Rotella and what appears to be a stock oil pump. On cold start she is running 80psi at high idle. After she warms up and idles down, around 30-32 psi. Not sure what it would be after a long trip until I can get a new switch installed. I'd imagine it would go lower when fully heat soaked and not just idling in the shop.

Is this too much oil pressure and would that be why the switch popped it's top? Or just a junk switch? Maybe both?

I am open to using different oil but I will say the engine runs great and seems happy.
 
Hey folks, looking to learn a bit about what others have been doing for a quality oil pressure switch. I replaced it at the beginning of the season and at some point over the last few weeks it stopped closing, keeping the light off at all times. This was a Standard Motor Product switch.

I replaced the failed switch with a TRQ switch which failed after just a few trips, easily less than a hundred miles. This switch failed opening so the light would not go off. Upon further inspection it actually "popped the top" and was leaking oil which explains why it wouldn't close.

Confused I decided to check the oil pressure.

I run 15w-40 Rotella and what appears to be a stock oil pump. On cold start she is running 80psi at high idle. After she warms up and idles down, around 30-32 psi. Not sure what it would be after a long trip until I can get a new switch installed. I'd imagine it would go lower when fully heat soaked and not just idling in the shop.

Those oil pressure values/conditions are good.
Is this too much oil pressure and would that be why the switch popped it's top? Or just a junk switch? Maybe both?

I am open to using different oil but I will say the engine runs great and seems happy.

If you have not purchased an oil pressure switch, you might consider this Niehoff AL-133A:
Screenshot 2025-10-19 2.30.30 PM.png


Available at eBay: Niehoff AL-133A

This NOS switch is likely better than any made in the last 20 years, and last indefinitely longer.

FYI...
 
Typically, nobody worries about cold oil pressure, just "hot" oil pressure at "hot base idle" speeds. The FSM has the pressure specs in it. www.mymopar.com .

10W-40 motor oil was around back then, but most people tended to use straight-weight 30 or 10W-30 viscosity ranges. At least down here in north TX.

The old Chevy 2.8L V-6 would consistently hit 90psi oil pressure on cold start-up, for reference.

CBODY67
 
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