bobmarshall..... 15w-40 is not what the 4.0 calls for, also that junky orange oil filter is known for being the cause of low oil pressure.... once again it has been found as a root cause of low oil pressure like yours on the 4.0. the 15w-40 isnt a huge issue except for at 58k there should be little wear on youre engine, that 15w-40 is starving youre engine of oil flow. put in some cheap 10w30 and slap a mopar or wix filter on it and see what happens to the pressure. i would imagine that it goes up.


the frams are known for their bypass valves being bad out of the box and a whole bunch of other things.

 

Aside from getting rid of the fram I would not be too concerned about it. You already checked the bearings,if it runs good and sounds good just drive it. Quit playing around with oils trying to get the pressure up. The difference in viscosity between 30 & 40 is insignificant at operating temperature. Even if you could magically increase pressure it would not add to the longevity of the engine. The only way to get pressure up is to tear the engine down to find the cause....a drastic approach if the motor is running fine. Life was simpler and drivers were happier when cars did not have oil gauges. Automakers have noticed the can of worms they created by installing oil pressure gauges. That is why cars built in the last few year have FAKE oil gauges...Jeep started this practice of installing dummy gauges in 2003 with the result of fewer warranty claims!

 

I don't doubt fewer people took their cars in - but how does that effect warranty claims? Doesn't a warranty claim imply that the mechanic at the dealership tested the engine and found it to be operating below specification? If you bring in your car complaining about low pressure, tech tests it, finds it's within spec, why would that be a claim?

 

How would the owner know he had low oil pressure if the gauge is fake?
He wouldn't unless his pressure dropped below 8 psi (that is what triggers the gauge to read ZERO and trigger the "check gauges" alarm.

 

Yeah I know. So he'd go into the dealership. My point is - if the gauge only drops to, say, 15 PSI, and the spec is 8, shouldn't the tech just tell them to go away?

 

?? the dummy gauges will never read 15. The needle only shows 2 positions; either mid-scale or zero. Any pressure >8psi = mid-scale, any pressure <8psi = zero. The spec for warranty is 13 psi. Get my point? Chrysler has padded that by 5 psi in their favor!

 

You're talking about the 'real' gauges, I think BBD is talking about the faux equivalent.
Some customers can make quite a stink, they don't take "it's normal" for an answer.
When their brand new Jeep reads 25# at idle and 50# at cruise while their neighbor's 'brand new Camry' reads 40# no matter what, they're convinced something's wrong and the motor is going to fail a week after the warranty expires.
They start calling the zone rep, their lawyer, the BBB, telling friends and neighbors (all of whom dutifully say 'my car doesn't do that') that the dealership is ripping them off... they create a real nightmare.
It's impossible to explain that there isn't a problem because the customer thinks you are lying. If you were telling the truth the neighbor's car would do it too.
The buffered idiot-gauges keep those people happy. It's as much a PR decision as anything else.

 

Do you know the Bob Marshall Wilderness area near Glacier National park, Rocks! (Iz just called "the Bob" sometimes). Just a thought, low idle speed will give low oil pressure. Maybe a slightly higher idle? (and here I can run straight weight 30w Castrol) I'm over 270K and it rarely freezes here though.

 

I absolutely understand that - we're on the same wavelength here. My point is that a warranty claim would specifically be a repair completed by a dealer under warranty, and for them to do so, the pressure would have to legitimately be out of spec. If your example customer comes in complaining about the 25 PSI pressure at idle, the dealer tech is going to test it and tell them that the minimum is 13 PSI, there's nothing wrong, please go away - but not do any repair under warranty. Or am I missing something here?

 

The dummy gauge will keep them away from the dealership in the first place! Remember the idiot lights that only came on at 2-4 psi? I can recall many mechanics telling a customer it was normal to blink on at idle.

 

Oh for sure - I also remember people thinking that you didn't need to check the oil until the light came on

Unless the fake gauge only comes on below spec it shouldn't make a difference. The only way it should impact repairs made under warranty is if the threshold is lower than what a dealer would pay to fix and people with legitimate problems aren't getting them repaired. Unless the minimum spec chaned at the same time...

 

Some of the old AMC owners manuals even stated it was normal for the light to flicker when idling or coming to a stop! In those days I wonder how many cars were running around with low oil pressure and the owners never had a clue.

 

I was told changing the oil pressure switch might help. I haven't done it yet but thought I would put that suggestion out there

 

The engine runs good, no knocking or pinging.

 

Drive it