Kap

Getting old, getting old.... and getting low oil pressure. How much can I expect a garage to charge me for putting in a new oil pump?
Here's the story
My 2000 Jeep Cherokee Sport eventually needed that new head at 100,000 mi last year when the old head suddenly developed the dreaded crack. Since then, I've had erratic oil pressure. I still get 40 at highway revs with 10W-30. Idle is about 15-17 which I am told was standard for it when fully warmed up. But when I go off road over the mud track in my timberland in 4LO for the usual 40 minute boneshaker ride to my cabin, things get hot under the hood and the oil pressure drops to zero at low revs.
Putting the shift in neutral and goosing the revs will bring it back up but not all the way. This is a new problem to me. A local mechanic let it idle for half an hour, checked the pressure, and told me the issue probably was the gauge. I don't believe it. I think it's the pump and he didn't get the motor hot enough to trigger the drop to zero.
So, any advice? and if it's the pump what's a fair price and how long would it take a different garage to do it?
As I say, getting too old to get into it myself. Thanks.

EZEARL

Did the mechanic check the pressure using a mechanical gauge?

Kap

Think so but I will ask. Thanks.

EZEARL

Even if he did but your still skeptical just do it yourself. When he says he suspects the gauge I'm guessing he's meaning the gauge sending unit.

TrailerTrash

A cheap mechanical pressure gauge takes about 10 minutes to install and you can verify the pressure for yourself. The factory gauges and sensors arent known for being really accurate.

bluejeep2001

10w30 is thin for temps mostly above 40. I have started using synthetic 10w40 in winter its as thin as dino 10w30 but holds up better for temp changes.. odds are its not your pump if it puts out goos oil press when cold at idle . Changing the pump is" easy". Drop the pan.....but it doesnt clear the axle ...unbolt shocks and track bar then jack up the frame to let axle droop...2 bolts and oil pump out...but again its probably not pump

BlueRidgeMark

The path from "erratic oil pressure" to "replace oil pump" is a not a straight line, or a short trip. There are a lot of other things to consider.

doublechaz

Seems like to me, low oil pressure is nearly never the pump. Race cars excepted, but your street whatever is certainly not cavitating in the pump at 10000 RPM and eroding the pump teeth.

About half the time 'low oil pressure' is either a measurement error or the wrong oil. The rest of the time we don't want to talk about that yet.

cruiser54

Oil filter choice is important. What brand are you using?