I had my 2013 GMC Sierra in the shop under warranty because I felt the oil pressure was to low. They replaced the oil pump and said it was good now. Well I got it back about 2 weeks ago and the pressure at idle was 20 when I got it back, but now its dropped to 17. At running it was 40 and now its dropped to 30. I am getting annoyed and feel like my truck wasn't fix after them having it for 6 weeks. Would it hurt me to put the Lucas oil stabilizer in there? I don't want them to have my truck for another 6 weeks and it not get fixed again. I need it for work.

 

How are you getting your oil pressure readings? I would not rely on what you are seeing on the dash gauge.

 

 

I tend to be old school and prefer mechanical gauges. If you can find an access point to the oil gallery, you can try using a good mechanical gauge and see if you get similar readings. You may also get more information from your DIC. I drive a 2015 Chevy 3500 van with the 6.2L engine and the oil pressure shown on the gauge at idle is usually 15 to 20 psi. Depending how recent the oil was changed, oil pressure goes from 30-50 psi on the gauge at highway speed.