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1997 318 4x4 oil pressure dropping

I have just recently bought a dodge Dakota with 160k miles on the engine.
the first problem that had showed up was the pressure gage would drop completely to 0 when at a stop light. and its not like I didn’t have oil in my truck either since I check the oil everyday before I start my truck and rarely have to add any. due to a small oil leak on the valve covers. I also a have to replace the oil pressure sensor. and this problem still preexist. so am wondering if I should get a new oil pump and bearing put in or run a thicker grade of oil in my truck. or do both.
also when the oil pressure drop in my truck it no linger stays at zero just stays at the bottom line before the warning light comes on after replacing the sensor now. I though trucks where suppose to run at 40 to 60 ibs of pressure.
sorry for all the typos not a computer person.

Usually when the oil pressure drops at idle with an engine with that many miles indicates a worn engine.


I recommend hooking up a mechanical oil pressure gauge and reporting the readings to us

any lower end noises from the engine?


well when I drive it doesn’t build all the time it stays at 20ibs
only when I first turn it on and drive it before it warms up all the way does it go to 40 to 60ibs

no lower end noises
should I do a oil flush?

What weight oil are you using?


sould I swap to 10-40 or straight 40?

Use the oil that the vehicle manufacturer recommends.

If the oil pressure drops off, the main/rod bearings may be worn.


how much does this normally cost to replace?
and my engine calls for 10-30. on the cap

A new engine.


ahhaahaha I wanna try to get another 100k out of it before dropin a new one in

Than how do you know your oil pressure is at zero? How do you know the sensor is bad? Have you checked the actual pressure with a good gage?

It doesn’t work this way. The oil pump fails to be able to maintain pressure because of excess wear on the bearings (plural), and these are the main (crankshaft) and rod bearings. Camshaft bearings are the same type of bearing, but they’re not generally the problem. It’s the main and rod bearings that take the biggest beating (sustain the greatest wear). The way the pump develops pressure is by forcing the oil between the bearings and the surfaces they protect. What happens is that when the spaces between these bearings and their corresponding surfaces become too great, the oil flows through too easily and the pump can no longer maintain the pressure. Oil pumps’ clearances are nowhere near as critical, and they spend their lives constantly awash in fresh oil and with very little load. They don’t generally wear out. In short, it isn’t as simple as replacing a “bearing”. It’s an engine rebuild.

But, before you do anything, you need to have the oil pressure tested. A tech can put a test gage on the sender port (he’ll “T” in it) and read the actual pressure.

Post the results.

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I will take it up to the local shop and have a tech test the oil pressure. and report the reading back to this form. and what happens if the pressure it correct as I read on the dash and or be wrong and it still holds pressure as it should at 40ibs

Your oil pressure at idle will not be 40psi. Typical when the engine is warm and idling could be as low as 8 to 10 psi. Pressure will rise as the engine revs rise. The amount of oil that the pump tries to force between the bearings and their respective surfaces rises with the speed of the engine, the spaces the oil is being forced trough does not. At 3,000 rpm, the pressure could be up to 80psi.

@vash6; You definitely need to have the oil pressure tested with a mechanical gauge with the engine hot and if the pressure at idle is below 10 and below 20 at 2,000 rpm you’re living on borrowed time. If the pressure is critically low and the temperature will remain above 40*F 20W-50 oil might add a few thousand miles to the engine before it throws something loose. Don’t waste the time and $ on flushing. Of course opinions vary, as always.

Oil pressure depends on the oil system design used for the engine and where the pressure is measured. On my 70’s Ford truck w/it’s original to the truck 302 v8, after the engine warms up for a minute or two the oil pressure according to the dash gauge measures around 40 psi at idle and 60-70 psi at higher rpms. That’s consistent with what the owner’s manual says it should be. My 90’s Corolla doesn’t have a dash oil pressure gauge but the factory service manual says the oil pressure at idle is much lower than the truck’s 40 psi; the Corolla is more like 5-10 psi at idle as I recall. And goes up in sort of a linear way with rpm to the 35-40 psi range. So first thing you need to do OP is find the engine specs on what your oil pressure should measure. Then ask a shop to measure it for you, at idle and several higher than idle rpms.

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Oil pressure SPECS for 1997 Dodge 5.2 is minimum of 6psi warm idling, 30-80 psi warm @ 3000 RPM. If you truly have 0, don’t run engine.

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