120scruiser replied:

Get somebody to do an oil pressure test with a proper guage and not just a guess from Nissan.
If these ZD30 engines oil pressure drops the first thing to go is the turbo.
I've had one fail in the oil pressure relief valve. Results in oil being dumped to sump and first thing to go was turbo then engine.
Hope this helps
120scruiser

Member - Ian H (NSW) replied:

Yes, I agree with Michael. Get an oil pressure guage fitted using a "tee" fitting at the oil pressure sending switch on the block(usually) keeping the Nissan guage connected and working. That is the only way to be sure of the actual pressure the engine is getting. Avoid any electrical "things" getting between you and the truth.
I had a mate with a V8 Commodore with a blinking oil pressure light at idle. He ignored it for months and finally fitted a pressure gauge as above and guess what. The maximum pressure he got was just enough to keep the idiot light off, even at high revs. Dirty crud from not changing the oil was blocking the pickup in the sump to the point that he had to drop the sump, remove the pickup screen and drill/dig the crud out. Engine still goes well after about 10 years but rattles a bit on cold start up. Those old V8s are tough if nothing else. Good luck, those Nissan 3.0 TD need all the care they can get.

Member - David 0 replied:

Do you have an oil cooler?

There are a couple of possibilities I can think of. Remote as they are, they have been reported from time to time.

Oil held up in a cooler or oil filter is not supposed to drain back to the engine in most 4bs. A failure of a non-return valve or failures in oil cooler can result in oil draining back to the engine giving a false high oil level (the system is partially drained). This means that once running the oil pump could starve.

In any case I wouldn't drive it while it shows low pressure. One thing you could try, is to for a very short run, overfill the sump NOT TOO MUCH and see if that improves the situation. You would only need to overfill by 500mls or so. Don't drive it for too long in this state though.

Voxson (Adelaide) replied:

It happened to mine also... Lakeside Nissan in Adelaide identified it straight away as a faulty oil pressure switch...
They said it is not uncommon in the 05 model...
They replaced it and now no problems...

Member - Oldplodder (QLD) replied:

Suggest as above. 'T' off another sneder and install another guage as a check.

Diesel of the 90 to 99 vintage pajeros have a similar problem with funny oil pressure readings.

After hassling the dealer when new it came out that the oil pressure sender is common between diesel and petrol, but the extra vibration of the diesel would damage the oil pressure sender after 20 to 40k to give funny readings.

Got ti mounted remotely off the firewall with a high pressure hose to the block and the problem solved.

Good luck. Found it took a while to sort out my problem.

Member - Hugh (WA) replied:

Hi Michael,

I've just come home from XMAS holidays and had same problem arise on my '03 3L Patrol last week. I took it to Giant Nissan in Osb Pk and service manager said it would be one of the oil pressure tx (apparently they have two). They are on order and will be replaced under warranty. He commented that he'd seen 5-10 vehicles with this fault.

Regards,
Hugh