Ok, so I have had issues with the oil pressure light and Gauge. Sometimes the light would go off and show I have little oil pressure. This week I changed the oil pressure sending unit. I also dropped the oil pan to make sure the pick up screen was clean, and it was. the guy I got it from told me he just changed the oil pump what that does look new. I put it all back together and did an old change. I start the truck and the oil light is off but even with a test drive the oil pressure shows it at zero. Not sure why the oil light went off if it's still not registering any oil. Any ideas? I have to order an manual gauge I dont have one but I am going to oder one to see that way. Any other ideas?

 

Whenever someone tells me they changed an oil pump, all my antenna's go up! It's rarely the oil pump that is failing. It's usually main and rod bearing wear causing low oil pressure. Or a blocked galley. And even if the oil pump did go bad, it's almost for certain that bearings are shot too.

I have no idea what engine you have. Hint, hint. But what I've done in the past is to take the oil pressure sending unit off, and start the engine, then shut it down immediately. If you've actually got pressure, oil will come out with a good bit of force and volume.

 

Put a mechanical gauge on it, and see what oil pressure really is. If it's that low, its rebuild time.

 

The engine is a 5.9 gas.

 

Yep unfortunately it’s most likely the bearings. Rebuild it or run thicker oil to get by until it blows.

 

Sorry about that

 

The gauge isn't necessarily a direct representation of actual oil pressure. Sending unit sends a reading to the PCM the light is set to go off at a certain low spec, but it might take a certain higher spec to trigger the gauge. You'll notice the gauge never reads between zero and the first hash mark. Actual pressure is somewhere in between triggering the light or the needle.

Definitely need a mechanical gauge to be sure, could always have a bad wire skewing the reading. However, based on your repair information I agree with the above. Lots of red flags surround this.

 

4 year old thread and the OP hasn't been here since then.

 

Caught me, I usually try to watch for that. Wonder if the above poster was a bot post, new account, just randomly posting sorry?

 

You see it a lot here and other forums, Newbies post a few times and they are gone. What usually happens is they post to a 10+ year old thread instead of making they own.