Matt69olds
Full Access Member
- Joined
- Jan 8, 2018
- Posts
- 2,453
- Reaction score
- 3,823
- Location
- Central Indiana
- First Name
- Matt
- Truck Year
- 81
- Truck Model
- GMC 1/2 ton
- Engine Size
- 455 Olds
Cut the oil filter open. If it’s clean of metallic debris, put a mechanical gauge on it to verify the oil pressure. If it’s still low, use 10W30 or 10W40. Shell Rotella 15w40 will definitely raise the idle pressure.
Having said that, thicker oil is a band aid. Something is worn to cause the lower oil pressure, the knocking sound confirms that. It might run like this a long time, it might get worse as time goes.
Having said that, thicker oil is a band aid. Something is worn to cause the lower oil pressure, the knocking sound confirms that. It might run like this a long time, it might get worse as time goes.
