my oil pressure keeps going down when my engine heats up it only goes above 40 then when it warms up it goes all the way to zero? on my 1998 gmc jimmmy 4x4 sle vortec engine 6cyl 4.3


Asked by Apr 05, 2015 at 03:34 PM about the 1998 GMC Jimmy 4 Dr SLE 4WD SUV

Question type: Maintenance & Repair

I have changed the water pump ,oil,plugs and plug wires,starter,and head gaskets all my gaskets on the motor so it was making a bad knocking noise now its quite but still knocks a little and when you start it it seems the oil pressure goes down as the motor heats up?

3 Answers


That's because of the worn bearings. Worn bearings will cause low oil pressure at idle when the engine gets warmed up. That's also what's causing the knocking sound. Time for an engine rebuild or replacement. If the bearings are that worn the rest of the engine is tired as well. HTH. -Jim

1 out of 1 people think this is helpful.

Thank you Js08016 is it worth fixing the bearings? or should I just junk it?

1 out of 1 people think this is helpful.

You're welcome. Glad to help. If you want to keep the truck and it's in otherwise good condition see how much a salvage yard engine would cost. Make sure you can hear it run before you buy it! As far as fixing the bearings, unless you plan on rebuilding the whole engine, I wouldn't bother. Rings, valves, camshaft and crankshaft, etc. are worn as well. You'd be putting good money after bad, in my opinion, to just do the bearings. HTH. -Jim

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