Oil pressure

[Silversage]

Anyone know the correct oil pressure readings for a 3.5l NM pajero?
My Gregory's manual only lists the NT and NS oil pressure's for some stupid reason, and they are very different

[pajmobil]

Haynes manual : 80 kPa@ idle

[Silversage]

That's for NM? i just went and checked a haynes (1997-2009) manual at repco, NM was not listed.

[pajmobil]

Haynes manual 1997-2005
V6 petrol engines 3, 3.5 and 3.8 litres oil pressure 80kPa@idle

[Silversage]

sweet, don't suppose you know what that is in PSI?

[pajmobil]

80 kPa=11.6 psi

[Silversage]

holy shit....that means mine is idling at 340ish Kpa......

[Pauly Faulkner]

Check the guage after engine is upto temp, 50psi at idle could indicate faulty guage/sender, blocked oil passages or could even be the oil cooler bypass valve staying fully open and not allowing oil to come upto operating temp(on models with an oil cooler fitted).
My 97' NK 3ltr used to sit at 50-60psi on first start then gradually come down to 30psi at idle, after i flushed all the oil passages etc when i rebuilt the top end it came down to 40-55psi on first start and 15-20psi after upto temp.

**oil pressures i mentioned are all idle pressures

[Silversage]

mine was 48-50 PSI at running temp @ idle, Temp gage was on Normal. the oil pressure was tested at a mechanics via a handheld mechanical gauge (used for testing oil pressure), my Oil light never comes on on the car (had it tested so it does work..lol) or will the oil light only respond to low oil pressure?, i Have an oil cooler on my car but i was under the impression it was for the tranny oil?

And i take it cleaning blocked gully's can only be done by pulling the engine down?

And one more thing are there any long term hurtful effects of high oil pressure?

[Pauly Faulkner]

Don't have to, you can just use lifter free or oil flush treatment, hydrocarbon based are usually better, stick it in the oil fill and idle engine for 30mins then drain and put in new oil and filter, it's wise to do this every oil change.
Auto trannys use a small plate type cooler in the bottom of the radiator, check the oil filter housing, you will see 2 hoses that run up and around the rad to the oil cooler. The cooler bypass is the big cap head nut under the filter on the oil filter housing, it's just a spring with a plastic head that moves from pressure to allow/block flow to the cooler. If oil cooler warms up as the engine is warming up it's faulty or the pressure is incorrect. It's unlikely to be the problem but just a thought.
And yeah oil light is for low pressure, 5psi I think.
What did the mechanic read the pressure as, in psi? Or is that where you got the 48-50 psi from? Also where did he check the pressure on the engine?
High oil pressure is better than low haha, but it can cause premature blow outs I suppose. The oil pump actually puts out in excess of 100psi at high revs but the excess pressure is bypassed back to the sump via pressure relief valve, not sure if it's located in the pump housing or if it's a part of the oil cooler bypass I mentioned

[Silversage]

Wow, thanks you are very informative, i flushed the engine with Lucas oil flush stuff the otherday, guess i should do it several time's, when i drained the oil after this i did notice thicker/sludgy bits coming out, ill do it a few more times i guess, he tested the pressure as PSI, and he plugged the gauge into the hole the oil pressure sensor goes in. it read between 48-50 kept moving up and down between them..so not a lot of movement

[Pauly Faulkner]

No worries champ, happy to share info
Just checked the manual etc and the hpr valve is the metal ball and spring inside the pump behind the pump rotor/cog retainer, pump needs to come off for that to be replaced. The oil cooler/filter bypass valve is just the large cap head nut/ bolt just near the pressure sender under the filter.

And yeah that flush stuff can take a few goes, if you suspect it's bad just add a bottle and drive it for 20mins so the revs go up a few times, the oil passages are rather tiny in and around the cam area and get blocked easily, don't labour the engine to much with the flush in as it thins the oil quite a bit. And use the hydrocarbon based stuff works heaps better, you can also buy anti sludge additives for engine oil, just hit up your local auto store for it.

[jol]

Haynes manual 1997-2005
V6 petrol engines 3, 3.5 and 3.8 litres oil pressure 80kPa@idle

Yes I know I've resurrected a really really old thread, but can anyone confirm the oil pressure figures for a 3.5L petrol. In the manual I have it says 4PSI min at idle, which is a bit different to what was suggested in this thread. (29Kpa ~ 4PSI). Am I looking at the correct thing - this is in the 2001 M/Y Service Specifications section I have.

[erad]

4 psi (28 kPa) is about right for idle. Pajeros have lower oil pressure than most other cars. The oil pressure switch operates at about 5 psi, so I guess that would be of the right order.

[le cheekster]

Check the guage after engine is upto temp, 50psi at idle could indicate faulty guage/sender, blocked oil passages or could even be the oil cooler bypass valve staying fully open and not allowing oil to come upto operating temp(on models with an oil cooler fitted).
My 97' NK 3ltr used to sit at 50-60psi on first start then gradually come down to 30psi at idle, after i flushed all the oil passages etc when i rebuilt the top end it came down to 40-55psi on first start and 15-20psi after upto temp.

**oil pressures i mentioned are all idle pressures

*****hi i have been trying to get some info for a week- whats the cold oil pressure dohc v6 cranking?- i have 23 ish psi. on 15-40w

rebuilt heads, every changable part swapped out, regular oil changes

can you pm me please?


cheers , jony