High Oil Pressure at Idle? 1990 S10 Blazer

brad1313

Hi all

I have a 1990 S10 Blazer Sport. It has a later model 4.3L Vortec engine in it... not sure of the year.

Anyway, lately, after the truck is warm and I'm sitting in traffic or at a light, the oil pressure rises. The gauge only goes to 80. If I put the truck in park or neutral it goes back down to normal or if I turn off the a/c it will drop back to normal.

I've swapped filters and changed the oil but the problem persist. It hasn't blown an O-ring on a filter or anything so I'm not sure how high its actually getting.

Thoughts?

Mr_Shiftright

I'd recommend inserting an analog pressure gauge into the engine just to see what's really going on here. Based on what you're describing, the symptoms don't make a lot of sense to me but that doesn't mean there's nothing wrong here. Possibly you could have an oil pressure relief valve at the oil pump being stuck shut or mostly shut. If the analog gauge verifies the extreme oil pressure, you may have to pull the oil pan for further diagnosis. Maybe it's really gunked up in there.

brad1313

I guess I'm going to have to figure out a way to get my hands on a gauge. What doesn't make sense is why kicking it out of gear or killing the air would fix the issue other than slightly increasing the idle speed. The stock gauge acts normal during all other conditions so I don't have a reason not to trust it... and like I said, truck runs great with no signs of any kind of oiling issue.

Mr_Shiftright

How's the oil level on your dipstick?

brad1313

I've got it right in the middle of the hashmarks right now... maybe to the low side. I drained a little out thinking it might possibly be a little overfilled... but the same thing still happened.

Mr_Shiftright

You'll have to verify your readings with a manual gauge otherwise you could be chasing a phantom.