What causes the oil pressure gauge to fluctuate on my 2004 Jeep Grand Cherokee Laredo?

To verify there is a problem, remove the oil pressure sending unit, replace it with a test gauge, start the car, idle, accelerate etc and watch the gauge for any abnormal variations it should react to evry change in acceleration and not be below the minimum or above the max as per the service specs.

If it is a 4.0 strait six cylinder this is a common problem on them.Mine was located just below the oil filter and is pretty easy to fix.Plan it on your next oil change and it is even easier to change out.Oh just so you know your 4.0 liter engines do make a little bit of noise but are pretty much bulletproof if you just do regular maintence on them.Next time you start it put your ear down by the driver side hood hinge.You will find some tapping noise there it is part of the evap system.If it had no oil pressure you would know it rite away.

judging logically by what you mentioned I would check the oil pump first.

How many miles? How many starts and stops? Are you using too high of a viscosity?

Not really , when you give it gas it creates higher pil pressure at higher engine speeds, when the engine slows down there is less pressure on the oil.

the 1st thing that needs to be done is have a mechanical oil pressure test gauge hooked up to confirm the actual reading, the electronic gauge many times is incorrect.

If you have zero oil pressure thats a BAD sign, first have a mechanic check what the engines actual oil pressures are.



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You'll need to determine if the oil pressure is actually changing, or if the sending unit or gauge is lying to you. Be certain the oil level is up to normal, then check the actual oil pressure with a test gauge. If the pressure varies (drops) at engine idle, perhaps your pressure bypass is defective, or perhaps the oil pump is worn. Testing with a known good pressure gauge should lead you in the right direction.

the sensor is located right above the oil filter, careful they crack very easily...but are really easy to replace...

OIL PRESSURE SENDING UNIT ON MY JEEP GRAND CHEROKEE LAREDO 1999
WHERE IS IT LOCATED AND IS THERE A DIAGRAM OR PICTURE LOCATION FOR IT

ANY SPECIAL KNOWLEDGE TO PUT IN?