Outer Limits 4x4 Board

I have the center gauge cluster with the oil pressure gauge. last night I noticed that the oil pressure dropped to almost 0 while waiting in line at the drive thru.

once the revs picked up it, the pressure picked up again to about 30 on the gauge.

But then while traveling along the M4 in 5th it dropped off again.

(checked the oil yesterday before going to work and if anything it is a little full)

Driving to work this morning same thing, but caught the traffic at roper rd and when I dropped back to 3rd/4th the oil pressure went back up, and then stayed up once I got back to 5th.

When I first got the pajero a few months back I noticed a similar thing but instead of going from 30 to 0 it would go from about 60 to 25/30.

Any ideas? (I'm going to drop it in to a mate tomorrow for a look)

I have the same problem on a NH V6. Was thinking possibly the oil pump is buggered, but I'm just guessing, really.
Please post if you find out what the problem is (really hopeing I don't have to change the oil pump )

it could well be the gauge sender unit. on my first paj(nj 2.8td) the gauge packed up at about 140,000km and on my current paj it was busted at 57000km when i bought it !!
they are not cheap though at approx $100. if mine goes again i will be buying 'normal' sender and putting a builb in the dash for the low oil pressure light. the connector is tied up next to the gauge sender unit.
cookie monster

the dam thing is now working again, so I'm pretty sure it is the sender. I might look at an aftermarket gauge and sender to replace it

Just a side point,

How old is the oil... ie months and Km's. For some strage reason here in Australia we have 15,000 k service intervals and well seriously that is way to long for any oil to be in a car, especially if that car see's off road use.

A natural part of combustion in a engine is to produce water and of course CO2. This water that it produces usually evaporates and goes out the exaust, that water that doesn't ends up in your oil, same as any unburnt fuel and carbon and......so on. It's the oils job to cope with this but after about 5,000 k's the levels end up a little high for the oil to be effective at handling all of this, The additives in the oil start to be non effective or have been used up.

So what's this got to do with a drop in oil pressure. Most proably the water and fuel levels have become contaminated enough that the oil's viscosity rating is no longer effective, the oil heats to quickly and is running to thin now. Time for a oil change. Another sign with the pressure gauge, is stop the car for a while and then when you go again the pressure will be fine, until the oil heats again in which case it drops again......

Of course if the oil is brand new then you have other problems but I would bet the oil is past it's used by date.

Natures Panorama wrote:Just a side point,

How old is the oil... ie months and Km's. For some strage reason here in Australia we have 15,000 k service intervals and well seriously that is way to long for any oil to be in a car, especially if that car see's off road use.

A natural part of combustion in a engine is to produce water and of course CO2. This water that it produces usually evaporates and goes out the exaust, that water that doesn't ends up in your oil, same as any unburnt fuel and carbon and......so on. It's the oils job to cope with this but after about 5,000 k's the levels end up a little high for the oil to be effective at handling all of this, The additives in the oil start to be non effective or have been used up.

So what's this got to do with a drop in oil pressure. Most proably the water and fuel levels have become contaminated enough that the oil's viscosity rating is no longer effective, the oil heats to quickly and is running to thin now. Time for a oil change. Another sign with the pressure gauge, is stop the car for a while and then when you go again the pressure will be fine, until the oil heats again in which case it drops again......

Of course if the oil is brand new then you have other problems but I would bet the oil is past it's used by date.

And people can (and some do) pay for oil tests, and often find that their oil is still going strong at the scheduled service interval. So there are no hard and fast rules on appropriate oil change intervals.

Just like not all vehicles "here in Australia" have 15,000km intervals, and those that do usually recommend 7,500km intervals if used offroad.

In the case we're discussing, the described behaviour is typical of Pajero oil pressure senders when they're on their way out, and doesn't necessarily happen 5,000km after an oil change - well, not to me, anyway.

Your prescribed test, of stop and wait, could also be proving that the problem with the sender is temperature dependent - and have nothing to do with the viscosity of the oil.

i change the oil in my paj every 5k, no way would i leave it for 15k or even 10k.
oil is cheap compared to other problems that can happen from bad oil.

-Scott- wrote:
And people can (and some do) pay for oil tests, and often find that their oil is still going strong at the scheduled service interval. So there are no hard and fast rules on appropriate oil change intervals.

Just like not all vehicles "here in Australia" have 15,000km intervals, and those that do usually recommend 7,500km intervals if used offroad.

In the case we're discussing, the described behaviour is typical of Pajero oil pressure senders when they're on their way out, and doesn't necessarily happen 5,000km after an oil change - well, not to me, anyway.

Your prescribed test, of stop and wait, could also be proving that the problem with the sender is temperature dependent - and have nothing to do with the viscosity of the oil.

Yes it could be just the pressure sender on the way out but as I gather this has just happened to him for the first time.

Of course in the test I describe it could also be the oil cooling back down and therefore the pickup having more pressure.

Natures Panorama wrote:Just a side point,

How old is the oil... ie months and Km's.

probably 2 months and about 1200 kms.

I've had no problem with it since (the regulator died though. But this has turned out to be a good thing, made me have a look at wiring in the engine bay, and some of it is shocking)

I change the oil and filter every 3000 - 3500 Km, Oil in Venezuela is very cheap. I have 310.000 km and I have never change nothing, not even the valve seals and water pump. This is the best truck I had. With proper service is indestrucctible, rock solid.