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installed my new oil pressure gauge from glowshift - results:

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cold start this morning (55* outside)

glow-shift gauge reading: 55 psi

dash gauge reading 45 psi


engine at operating temperature after 20 min drive (60 mph) at stop light

glow-shift gauge reading 32 psi

dash gauge reading 22 psi

glow-shift oil temp reading 187*


10 PSI difference between dash gauge and glow-shift gauge.  makes me wonder a few things:

  • can i lose 10psi from bottom of engine (where the glow-shift adapter is at, at oil filter) to top of engine (where OEM OPSU is located)?  OR
  • is my OEM OPSU Jacked?
  • what gauge would you trust now?



oil 2.jpg

temp 1.jpg

oil 1.jpg

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I would install the new factory sending unit, make sure you get the "new" one, it hasn't a screen in it that you can see if you look at the wet end.

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Yes, there can be a difference in oil pressure readings, how much is tough to say. But the further away from the pump it is, usually the less oil pressure it will read.

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my mechanic is hesitant to replace the OPSU.  he has done it too many times with no change and clients demand their money back.  and he is insistent that the manifold needs to be removed.  he feels i will be wasting $300.


maybe I will just attempt it myself.

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There is a reason the TSB for oil pressure uses a test block at the oil filter and not the 'dummy' gauge in the dash as you are learning.


There is nothing wrong with your OPSU. It's the calibration in the dash gauge that is the issue and not fixable. Water temperature is way worse. 


Relax and enjoy your new gauges. 😉 

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thanks, grumpy bear - I believe this to be true.  my buddy was pulling his 32' travel trailer and he got the low oil pressure warning with all the bells and whistles blaring at him.  he heard no engine clatter - drove it another 1.5 hours that way with no issues to the engine.  just turned up the radio to drown out the alarms - lol


not sure I would ever want to take that gamble.

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so, took the trailer out for our first trip over the weekend.  Truck drove like a dream.  no issues.  Glow Shift gauge always read 10 PSI higher than stock gauge.  Lowest my pressure ever went per the stock gauge was 20 PSI (at stop lights) and glow shift read 30 psi.

maintained 38 psi (stock) 48 psi (glow shift) while towing at 65mph (2500 rpms +/-)


based on this, i think last year's oil warning situation was a fluke.

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