My oil pressure gauge sits at 1/4 on the gauge when at idle, while driving it is usually a little over the 1/2 way mark, but alaways goes back down to the 1/4 mark when at idle.

is this normal? should I switch to synthetic oil would that make a difference? 2001 trailblazer 113000 Kms.

thanks

 

I believe your oil pressure gauge is the same as the one in my Bravada (and as attached below). If you are at 1/4 mark at idle, this means that you are holding somewhere around 20psi which is more than enough at idle. While driving down the road, you are at around 40psi which again, is more than enough to protect the engine. GM maintains that anything below 8psi at idle and something like 15psi at 2000rpm is a concern. Seeing as you are well over double each of these, you are fine.

Every engine is different though. My Bravada runs at 40psi when cold at idle, drops to somewhere around 30psi when warm and idling and when I'm driving down the road I read around 60/45psi cold/hot respectively.

Switching to synthetic shouldn't really affect the oil pressure by much if at all. The pressure is really determined by the pump clearances and the clearances on the bearings. As the pump wears, the clearances inside it allow for recirculation which will decrease its pressure capability. As engine wears, the clearances get larger and allow more oil to bleed off as it flows through the pressurized side of the oiling system. Now if you were to change to a heavy weight gear oil, you may see the pressure rise just due to the viscosity change, but I wouldn't suggest doing anything like that.

[IMG]local://upfiles/667/245E182E59FC4678B840A02AF5CAE3E2.gif[/IMG]

 

Yes, This isin the normal oil pressure operating range, Iwouldmake the move towards usingsynthetic oil at the 113,000 mark, andusing synthetic oil will not change your oil pressure reading's on the guage...

 

2001 4.3L engine vin code "W", RPO L35.





[*]Oil Pressure - Minimum - at Normal Operating Temperature [/ul]

42kPa at 1,000RPM
125kPa at 2,000RPM
166kPa at 4,000RPM

6psig at 1,000RPM
18psig at 2,000RPM
24psig at 4,000RPM