Low oil pressure on startup (1 Viewer)

[Estancio]

1987 BJ70. 3B engine. 467,000km on engine. In recent months I have noticed low oil pressure during startup. It has been slowing getting worse in the past year. There was nothing that really happened, I have just become more and more aware of it recently.

The needle hangs at the bottom for 5-15 seconds at times before it rapidly moves up to normal. Oil pressure is fine when running and I have not seen anything unusual except at startup. Last week the engine actually shut down as it registered low pressure. This often happens to me on the re-start after changing the oil.

So I need some help -- where should I look for the cause and remedy?

 

[David*BJ70]

What oil grade ?

That happens to me, too, sometime after oil change.

To make sure, use a mechanical oil pressure gauge. Replace the oil pressure sender or use a T. The oil pressure sender who talks the cluster gauge is the big one. The small oil is the oil switch that talks to the EDIC (who shut the engine when the pressure is to low)

You should read anything between 36 to 85 psi at 3000rpm (warm) and anything above 4.3psi at idle.

I do not trust the OEM oil pressure gauge on my 20 + year old Cruiser.

 

[Estancio]

Been using Shell T6 synthetic for about 2 years (5W40). Before that used Mobil 1 synthetic 10W30. Given the 5W versus the 10W, would I be wise to go back to Mobil oil for better startup pressure?

Adding to above, the Cruiser only burns about a half-liter of oil every 5000 km. I do oil changes at 10,000 with the synthetic.

When I return to the Cruiser, I will hook up a mechanical gauge to check pressure.

 

[lostmarbles]

I fill my oil filter 2/3rds full of oil before screwing it on to reduce the time taken to fill it (as well as smearing a little oil on the rubber sealing ring)..

But of course you can't prefill your filter if you have one of those crazy upside-down mounted jobs..

 

[roscoFJ73]

1987 BJ70. 3B engine. 467,000km on engine. In recent months I have noticed low oil pressure during startup. It has been slowing getting worse in the past year. There was nothing that really happened, I have just become more and more aware of it recently.

The needle hangs at the bottom for 5-15 seconds at times before it rapidly moves up to normal. Oil pressure is fine when running and I have not seen anything unusual except at startup. Last week the engine actually shut down as it registered low pressure. This often happens to me on the re-start after changing the oil.

So I need some help -- where should I look for the cause and remedy?

I wouldn't be too concerned. Its obvious the engine has some wear that's costing you oil pressure. What you need to do is plug in a mechanical gauge and take measurements according to the FSM.
Oil pressure at idle is not that important,going down the freeway at 3000rpm is when you really need it.
As long as your engine is pumping oil ,it will go for a long time yet with a gentle foot.
Change to a thicker oil. An old engine will be fine on 50 grade in your summer.
I wouldn't bother with synth,its probably way past the point of getting any benefits from that.

 

[Estancio]

Lostmarbles, yes I do have a crazy upside down oil filter. Cannot pre-fill it before installing.
RoscoFJ73, the engine has always run on synthetic so will there be any downside to switching to dino oil?

 

[bigbrowndog]

Should have less oil leaks. With our 2H motors in the tropics it pays to switch to heavier oil after 120,000 Ks.

 

[Estancio]

Thanks. Will go to heavier oil at next oil change.
Hopefully it might slow down the leak from my rear engine seal.

 

[fjbj40]

Concerning the upside down filter. Yes you can pre fill before starting. I should say add oil. I half fill mine and let it sit for 5-10 minutes and this actually soaks into the dry filer material. I then put a funnel in the new oil jug and pour out the oil that has not soaked in. There usually is very little. Doing this often does not cause the engine to shut off after the oil change.

Cheers,
Daryl