TD42 No oil pressure on startup!

[4x4boi]

Hi all, i was just wondering if anyone has an idea what is causing my patrol to get no oil pressure for 20 to 30 seconds on start up?

When it is started the oil warning light is on and the pressure needle reads zero and after a short while the needle moves and the light goes out. Im pretty sure it is not the sender unit because you can hear the engine rattle nasty until the needle moves and it smooths out! :confused:

This started out being only a couple of seconds a few months ago but is gradually growing worse and worse. Once it has the pressure it sits at 2 pound on idle and 4 on the highway, so its fine once its going.

ts a fairly old motor, has done 590,000k's and i dont think its been rebuilt at all. I serviced it only about 3000km ago at the most using a 15w 40 diesel oil.

Any ideas? im sure its just going to be a case of run it until it dies and get a new motor, but you never know!

Alex G

[Atrol]

Might be a bit to do with the oil being a bit thin for an older high mileage motor. Mine has 340 000 and i had 15w40 for 5000ks and the oil light stayed on for a few secs on start-up, little rattly also, changed to penrite HPR Diesel which is 20w60 and it runs quieter and better.

[beast3805]

590 thousand thats doing darn well! ye just give a thicker oil a go and see how it goes, if its off to much concern it would be time for an engine rebuild id say hehe

[Yom]

also the oil filters could be blocked.

change brand of oil filter, the current ones might have poor anti drain back valves.

but at almost 600,000km on original components its also possible she's just tired and slowly giving up on life. 30 seconds to build pressure? I'd imagine this is the case.

[4x4boi]

Okay, well i will try and change the oil type and filter brand and see if that makes a difference. Just a question though, im not a whiz with oils, and to me i thought a thin oil would take less time to build pressure than a thick one? How does this work?

[Yom]

Okay, well i will try and change the oil type and filter brand and see if that makes a difference. Just a question though, im not a whiz with oils, and to me i thought a thin oil would take less time to build pressure than a thick one? How does this work?

You're absolutely right... ;) lol

The thicker oil will help hide the wear in your oil pump.

[DirtyJ]

I had this problem a while ago when I used Valvoline or Ryco filters... Changed to genuine Nissan ones and the light goes out in 2-3 seconds now. I get the genuine nissan filters for the same price through a wrecker now.

[mattsmav]

i also have lower oil pressure im my mav coming up 450 thou but running quality oil like penrite and thicker works for me.also oil presure gauge is it supose to be instant or rise slowly like fuel gauge after filling????

[Blaktop]

Oil pressure gauge should be more or less instant. My old '90 GQ used to take 10-15 secs to build up pressure. When I bought it it had done 230k and the idle pressure was pretty low, was fine at revs. I dropped the sump and put a new set of bearings in it.....it still took a little while to build up pressure but the idle pressure was much better.

[CatMan]

I agree with Yom & DirtyJ about the filters. I've always used Ryco's, but had to buy an alternate brand when there were no Ryco's available & found the oil pressure to take about 15 seconds for the light to go out. I tested the oil pressure with a gauge & found it to be OK, so sourced some Ryco filters & the oil pressure light was back to a few seconds.