Random drops in oil pressure. 5.7 vortec

[Dixietruck]

While driving my truck will randomly drop to zero oil pressure, and the check gauges light come on. It will stay like this for 5 seconds then return to normal. Is there a sensor to go bad or something. I find it hard to believe the oil pump would go out after the easy 123,000 miles on the truck.

 

[jnewkirk77]

Does it happen on sudden starts/stops/turns or in normal movement of the truck? Does the engine sound any different when it happens?

It could very well be the pump, but with mileage that low, I'd hope it would be something as minor as the sender.

 

[Dixietruck]

Does it happen on sudden starts/stops/turns or in normal movement of the truck? Does the engine sound any different when it happens?

It could very well be the pump, but with mileage that low, I'd hope it would be something as minor as the sender.

There are no unusual sounds no knocking or valve sounds. It happens on normal movement.

 

[east302]

How is your oil level?

If that’s good, then it’s either a bad gauge (instrument cluster), bad sending unit, wiring issue between the sending unit and cluster, or a mechanical issue.

The gauge sending unit is in kind of a crappy location by the distributor. Ideally, you’d swap the sending unit out for a mechanical gauge to see what the real pressure is.

Or swap in a junkyard cluster and see if the issue is corrected; you’d swap over the odometers if you were keeping it.

Or swap out the sending unit. There is an actual diagnostic that GM uses to check the sending unit function, but I’m not sure if you’d need a special ($$) Kent Moore tool or not.

 

[RussKincaid]

One thing I have seen small blocks do is loose the pickup tube off the oil pump. It still picks up oil normally except once in a while it will pull in a bubble of air. The oil pressure drops suddenly then returns to normal like you describe. Usually low oil level, uneven terrain and high speed cornering causes it to drop, but i would definitely rule it out as a cause by checking before just assuming its electrical.