Zero Oil Pressure (1 Viewer)

[FJtimr]

Greetings Brain Trust, my 87 FJ60 had a low oil pressure issue that I am looking for advice
1. Driving around town pressure is fine (above middle on gauge)
2. Driving on the freeway it will stay fine for awhile (10 mins) then drop all the way down
3. I can get the the pressure to come back up if I get off the gas and push in the clutch
4. This happens after 55 MPH continually, if I stay below 55 it stays pretty consistent

Any thoughts or additional questions I can answer? Thanks for your advice.

 

[Godwin]

Greetings Brain Trust, my 87 FJ60 had a low oil pressure issue that I am looking for advice
1. Driving around town pressure is fine (above middle on gauge)
2. Driving on the freeway it will stay fine for awhile (10 mins) then drop all the way down
3. I can get the the pressure to come back up if I get off the gas and push in the clutch
4. This happens after 55 MPH continually, if I stay below 55 it stays pretty consistent

Any thoughts or additional questions I can answer? Thanks for your advice.

Put a mechanical gauge on it so you know exactly what the oil pressures are instead of going by the stock unit. Of the several 2Fs and the 3FE that I have, and all with high mileage, oil pressure at idle drops to 40 and at rpms over 1000 rises to 60+ and holds steady.

 

[FJtimr]

Thanks Godwin. Will do that, the only challenge is that when I drive around town below 55 mph there are no issues. When I am on the freeway over 55 mph it drops like a rock. I’m not sure I will see a drop just revving it. It seems to happen 8-10 minutes into freeway time.

 

[LCnAZ]

Sounds like you are "tickling the dragon." For the sake of peace of mind, I installed an oil pressure gage and 4psi alarm. You can see here. Builds - Sentimental Restoration of Family 1990 FJ62 - https://forum.ih8mud.com/threads/sentimental-restoration-of-family-1990-fj62.1095049/page-10#post-14126142

That doesn't get to the cause of your indications, but @Godwin the wise is making a very good suggestion to find a verification means of some kind.

 

[Spike Strip]

If Oil Pressure drops while driving, could be a clogged oil filter.

I'd change oil/filter and run a good 20w50 and see how she rolls.

 

[FJtimr]

@Godwin @LCnAZ @Spike Strip apologies for the delay response, I ended up changing oil filters and oil and through that process discovered my oil sensing line “may” have been intermittently connected. So I am not sure which culprit it was but it’s solved. Thanks for your answers, insights. Super helpful. Tim

 

[Sacto60]

when i did my side cover gasket I had to remove the oil sending unit/line... when i replaced it i had to be really careful on reattaching it in the correct spot otherwise i'd get some low/no oil pressure reading.