Ok, I have had this problem before and I thought I had it resolved. I was going over to a friends house for dinner and looked down and noticed my oil pressure gauge was at near zero. This has happened before and there was an iffy splice that I fixed and have not had the problem for several weeks. When I start the truck, the oil pressure idiot light comes on and goes out when the pressure comes up. My question is, if I really didn't have any oil pressure, can I expect to see the idiot light come on? I am heading home, around 350 miles on Sunday and it is really nerve racking to have no pressure on the gauge. The oil level is good and it is not heating up and there are no strange noises coming from the engine. It would just be a little more comfortable on the trip home to know that at least the idiot light is working, thanks guys...Mark

 

I believe the red light for low oil pressure only comes on when the gauge is also reading low. Mine is on when my truck is off and the key is turned towards ignition because the oil pressure gauge reads 0.

At least that's how i've always thought it has worked.

 

I thought that too, but the gauge is reading nothing at times and it doesn't come on, I'm confused...Mark

 

I'm pretty sure the idiot light is triggered by the readout from the sensor. A faulty sensor can be the problem. My sensor went bad and would give me a low or no reading on the gauge and the idiot light would come on sometimes. Usually at idle.

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Thanks, so it is possible that if my gauge is bad for example, that the idiot light might still warn me if I have low oil pressure? Thanks...Mark

 

The idiot light is driven by an on/off switch in the combination sending unit. The oil pressure gauge is driven by the wiper on a rheostat in the same unit. If the wiper gets worn or dirty and opens up, the gauge goes down. In a dirty old diesel it happens a lot.

If the idiot light is out, drive it. No worries.

When you get to it, the sender isn't a very expensive part.

 

Put a mechanical gauge on the port above the oil filter if you're concerned.

If the oil pressure checks out its probably just the sensor on the side of the block under the ip. That's what was causing my issue, which was causing very similar symptoms.

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That is what I was hoping to hear, makes me feel batter about the drive home. The cost is not important, the sender is unobtanium in Mexico, so I will order it and change it out at home, thankls Mark

 

Thanks, while I might be able to find a gauge here, But I think I'll just wait and do it when I get home...Mark

 

My gauge had a lower than normal reading, cleaned the connection where it plugs into the sending unit and right back up to normal
Del

 

I had an inoperable gauge and no idiot light when I bought my truck, new sender, viola!! Fixed