I have a 2007 silverardo Z71 4x4 LTZ with a 6.0 vortec max. The truck has 105K on it. Runs great. The oil pressure gauge starts to drop after about 50 miles into a trip. It falls all the way to zero and sets off the alarms on the dash. There is no lifter tap or knocking at all the truck seems fine. I replaced the oil sending unit about 2 weeks ago and thought all was well. The problem has returned. Any help would be great.

 

50K mile trips??!! No wonder pressure is dropping off, you're probably running into the ocean. Haha

 

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The oil pressure sensor may be causing the problem. This is just a suggestion, not a diagnosis. I encourage you to take the vehicle in for an inspection. A certified technician should be able to offer a more accurate diagnosis after a physical inspection.

If you have additional questions, please feel free to contact me.

Louis
GM Customer Service

 

I had the same issue happen once to me, and believe it or not, I was about a qt short on oil after an oil change. I put in a quart and the problem went away...I wouldn't have thought it would drop pressure to 0 but it did.

 

The oil is dead on full on the dipstick. I was told it could be in the cluster. I know the old body style trucks had cluster problem not sure about the new ones. Its driving me nuts!