1KZ how much oil pressure ?

[ceejay LC100]

Hi all,

My 1KZ has fairly low oil pressure at idle and even at 2500RPM, is only JUST at the lower mark of the acceptable level.

I will install an external gauge and check how much I'm looking at in PSI but till then can folks tell me if these in dash gauge readings look too low ?

What pressures should it have in PSI ?

I just changed oil and filter. Oil is SAE40 at the moment. I want to run it a little and change it again to flush the engine without using and engine flush.

Milage on the engine is un known. Starts instantly, no smoke. Supposed to be very low miles

The low reading in the pic is at idle. The higher reading is at 2500 RPM

 

[roscoFJ73]

I don't have A 1kz t manul with me but I can tell you that all Toyota diesels are pretty much the same.
The pressure at idle is not all that important provided there is some pressure,around 4-5 psi minimum.
Enough to keep the oil circulating is all you need,it is at high speeds where you need the pressure
At high rpm 39psi. is the minimum with 60 being ideal.

The test for the 1HZ requires a warm engine to be held at a constant 2500rpm(I think) for 2 minutes and the oil pressure is not to drop off.
You need to download a manual and check the figures. There was one available on a European site few years back.

Dash pics look ok to me and the fact it starts easy cold with no smoke pretty well sums it up that you have a good engine.

 

[Gun Runner 5]

Your idle and higher RPM oil pressure looks normal based on my experience.

 

[kbushnz]

Yup that looks like what mine does... When its hot... Bit more pressure at idle when cold....But thats to be expected...

 

[ceejay LC100]

Hmm mine is better when cold too. I wonder why the gauge has a normal operating range marked and none of us r operating in that range ?

Bad oil pumps ?

May be I'll try a 50 weight oil.

My ambient air temp is 95f so road temps get very high.
May b the engine will like the thicker oil.

 

[Locked79]

Toyota gauges aren't know for being too accurate. Installing a good quality mechanical gauge will tell all. On my old 1hz the needle would regularly fall below L and the oil pressure was fine

 

[AdventureRider]

Hi, I got a 1KZ and did a full rebuild. I tested the oil pressure with a gauge and it showed me 25psi in idle but when I rev up the car it would go up to 70psi. I run for break in HYUNDAY HEAVY Duty truck oil 20/50 mineral.
The engine is in a LEXXUS 80SERIES. When the sender unit was off and no cable on, with the mechanical gauge outside attached, I could actually see, inside the car on the dashboard, how the oil pressure gauge was going up to 75% and standing at quarter in idle. Very strange.
I put the sender unit back and the cable on but since that the gauge doesn't move at all. Anyway...
What are the exact PSI the 1KZ should have? And if oil pressure is high on a external gauge, should I be worried?
Could it be a blockage somewhere?
I used Molybdenum grease to assemble the engine.

 

[coldtaco]

20-50 might be a bit thick. I would think 15-40 is more appropriate. With a fresh rebuild and cold engine your oil pressure is going to be on the higher side until the oil warms up, of course depends on where you live too

 

[AdventureRider]

Thanks for the answer. I live in Cambodia with a average temperature of 30°C. More likely 35°C.
At idle after warming up its around 23psi. When I rev up it goes up to 80psi. Unfortunately the camshaft gets just a slide layer of oil on the lobes. Its not like on other engines that the lobes are spraying oil all over the place. I think after 100km I will change the oil filter and go for thinner oil. Unfortunately all thinner oils are semi or fully synthetics. We don't want that for the first 1000km at least.

 

[roscoFJ73]

At idle after warming up its around 23psi. When I rev up it goes up to 80psi

My 1HZ did that after a rebuild. I forget the idle reading , but the 2500rpm psi was smack on 80psi. Toyota Australia recommend 15-40 oil for the 1KZ..
I would have gone for a thinner oil for break in.

 

[duncanrm]

Factory spec.. from the 1KZ-TE FSM

Pretty sure there's a typo in it though.. that 43psi should say 4.3psi.

 

[AdventureRider]

Factory spec.. from the 1KZ-TE FSM

View attachment 3003845

Pretty sure there's a typo in it though.. that 43psi should say 4.3psi.

Hi, thanks for all your support.
Yes and No, its a bad print. Its suppost to be 4.3psi on idle.
I am always running 20W50 mineral oil in my 1HDT, so I thought I just run that for the break in on the 1KZ on the break in as well.
Unfortunately we can't find any mineral oil at 10 or 15w 40 API CF specs here in Cambodia. So I had to bit the bullet and use a semi synthetic after the 1st 100km on break in.
I hope that drops the oil pressure a bit.
I know that the diesel from Toyota always run very low on oil pressure as I am used to that on my 1HDT.
So I was a bit curious why it runs so high on oil pressure.
I replace all the bottom end bearings and I was also very care full with all the gasket surface and the use of rtv on it. Hope I didn't block up some oil galleries. Would be fatal.
Engine runs smooth though.

 

[AdventureRider]

My 1HZ did that after a rebuild. I forget the idle reading , but the 2500rpm psi was smack on 80psi. Toyota Australia recommend 15-40 oil for the 1KZ..
I would have gone for a thinner oil for break in.

Thanks for that advise. That helps a lot. And yes I changed the oil to 10w40...unfortunately semi synthetic. No choice!