Oil pressure gauge problem

[saleen bob]

I own a 2003 Denali with 200,000 miles and a 6 liter engine. My oil pressure gauge maxed itself out today. It normally has 40 psi of oil pressure. Today it showed 80 psi. Has anyone seen this happen and what might be the cause.

Thanks

 

[Dennis C]

Same thing happened

While pulling a 2000 pound trailer last week, it shifted into lower gear and the oil pressure went to 80 psi when the engine rpm went to 4000 rpm. Problem is, it didn't come back to 40 psi. Not sure if it is the guage, sending unit or oil pressure problem. Would appreciate any help or suggestions. Engine runs fine, no knocks or leaks.