Oil pressure gauge sits new normal position?

[feralyouth]

here’s a strange event. So since I bought this LC the oil pressure has always sat around center at idle than rose to the 3 line under load. I’ve done a couple oil changes now and no change, replaced belts, no change.

Now I did a 350 mile round trip, towards the end of the trip I noticed the oil pressure was lower but still in the middle ish at idle. Figured I had low oil, but I had to take the kids somewhere. On the way back my oil pressure dropped just below the second line and dipped further to the middle of the line 1 and 2 at idle. Got home added a quart, oil level was good but no change. Heard the belts squeezing so I checked the tension and it was way low.

So I did an oil change 10w-30 and tensioned the belts to 100 lbs. now my oil pressure gauge sits just below the second line and goes up to half way under load.

What the hell happened? Did I mess something up?

 

[AussieHJCruza]

What oil filter are you using?

 

[jonheld]

Oil pressure has nothing to do with oil level, unless you're so low that the pump is sucking air.
Viscosity and filter flow will affect oil pressure. Always use Toyota filters.

That said, the factory oil pressure gauge is notoriously inaccurate, but I would be concerned if I noticed a drastic change in position. Did you change the brand of filter or the oil viscosity or change from regular to synthetic?

 

[feralyouth]

Oil pressure has nothing to do with oil level, unless you're so low that the pump is sucking air.
Viscosity and filter flow will affect oil pressure. Always use Toyota filters.

That said, the factory oil pressure gauge is notoriously inaccurate, but I would be concerned if I noticed a drastic change in position. Did you change the brand of filter or the oil viscosity or change from regular to synthetic?

Mobile one filter. Bought it from an older gentleman that took it to random places for service. So I stuck with non oem since the badge was always good.

Always had synthetic oil.

I’ll switch the filter. Think I can change it without draining oil?

 

[Kernal]

"So I did an oil change 10w-30 ---- now my oil pressure gauge sits just below the second line and goes up to half way under load."

That's not too far of from what I've seen in three FZJ80's once the engine is warmed up (if not lower) depending on the oil viscosity,
rpms, ambient temps, etc, etc.

Already mentioned, if you're still concerned you could ask any mechanic to check the actual oil pressure (likely charge you one hour of labor).
He can screw in (IIRC) a 1/8" BSPT threaded adapter (British Standard Pipe Taper) in place of the oil pressure sender/sensor and attach a mechanical oil pressure gauge to get real numbers.

A defective/dead oil pressure sensor or a broken or poor connection at the oil pressure sensor could
cause erratic or no readings (IME more likely to have zero movement of the gauge).


If you change the oil filter consider draining the current oil and collect a sample of the used oil and send it off to Blackstone Laboratories for an Engine Oil Analysis. At a minimum the results will give you a baseline to see how your engine is wearing (metal levels ppm) but can also show if the oil is contaminated with fuel or coolant.

Then install a new Toyota filter but also change your engine oil to something like ~10W-40 +/- and see where the needle goes. Been discussed a lot
in the past but many of us on the forum run a heavier weight oil than what is printed on the oil cap (5W-30 US models) depending on ambient temps.

Blackstone will send out free collection bottles, quicker if you call them directly. If you pay for 6 tests in advance you get free shipping.

Oil Analysis | Blackstone Laboratories

Learn what's going on in your engine with oil analysis. Our free kits are easy to use and we explain the results in plain English! Since 1985.

www.blackstone-labs.com

Bulk Samples | Blackstone Laboratories Bulk Samples

Get a discount on your oil analysis by prepaying in bulk! The more you buy, the less per sample. Free shipping!| Blackstone Laboratories

www.blackstone-labs.com

 

[feralyouth]

"So I did an oil change 10w-30 ---- now my oil pressure gauge sits just below the second line and goes up to half way under load."

That's not too far of from what I've seen in three FZJ80's once the engine is warmed up (if not lower) depending on the oil viscosity,
rpms, ambient temps, etc, etc.

Already mentioned, if you're still concerned you could ask any mechanic to check the actual oil pressure (likely charge you one hour of labor).
He can screw in (IIRC) a 1/8" BSPT threaded adapter (British Standard Pipe Taper) in place of the oil pressure sender/sensor and attach a mechanical oil pressure gauge to get real numbers.

----------------------------------------------------------------------------------------------------------------------------------------------------------

FWIW if it gets worse or if you really want to get into the weeds:

Some things that could cause a drop or loss of oil pressure:

Significant dilution of the oil (fuel, coolant)
Severely worn bearings (inside the engine)
Defective oil pressure relief valve
Loose crank bolt (in the 1FZFE)
Internally defective oil filter
Severely worn oil pump
Plugged oil pick-up tube (screen) or oil galley's
Oil pick up tube that's loose (inside the oil pan)
(probably missed a few others)

A defective/dead oil pressure sensor or more likely a broken or poor connection at the oil pressure sensor could
cause erratic or no readings (IME more likely to have zero movement of the gauge).


So now that you're more worried than before you asked the question, if you change the oil filter consider draining the current oil and collect a sample of the used oil and send it off to Blackstone Laboratories for an Engine Oil Analysis. At a minimum the results will give you a baseline to see how your engine is wearing (metal levels ppm) but can also show if the oil is contaminated with fuel or coolant.

Then install a new Toyota filter but also change your engine oil to something like ~10W-40 +/- and see where the needle goes. Been discussed a lot
in the past but many of us on the forum run a heavier weight oil than what is printed on the oil cap (5W-30 US models) depending on ambient temps.

Blackstone will send out free collection bottles, quicker if you call them directly. If you pay for 6 tests in advance you get free shipping.

Oil Analysis | Blackstone Laboratories

Learn what's going on in your engine with oil analysis. Our free kits are easy to use and we explain the results in plain English! Since 1985.

www.blackstone-labs.com

Bulk Samples | Blackstone Laboratories Bulk Samples

Get a discount on your oil analysis by prepaying in bulk! The more you buy, the less per sample. Free shipping!| Blackstone Laboratories

www.blackstone-labs.com

Well I replaced the oil filter with Toyota oil filter and the level went back to the normal ( halfway then 3 line for awhile then sunk back down. checked all levels and the pressure is slightly higher but not much…. Engine sounds great. The first oil change I did the oil was very clean. I’ll have to get my pressure checked.

 

[Kernal]

Sounds like your oil pressure is in the normal range.

 

[cahill]

@feralyouth , one thing you may want to check is the wire harness that connects to the oil pressure guage. The harness is in the right front engine bay. At end there are three branches: one branch connects to the AC pump and the other two are on the oil pressure gauge on the passenger engine tucked up a little behind an exhaust manifold. The other end clips to a connector on the passenger wheel well. It is just those 4 clips and is only about 2 feet long. It is very easy to remove and inspect. I had this happen recently and found that one of the wires had broken near the connector. I just re-connected it at the plug and it works again. Here is a link to other posts that helped me.

Oil Pressure Gauge FIX

Well, like many on here, I’ve experienced the dead oil pressure gauge in the dash of my 80. While most would probably say, “replace the gauge and move on”, I am really cheap, and felt like taking the dash apart… Cliff notes: I ended up bending the gauge internals to get it to read again...

forum.ih8mud.com

 

[cahill]

Here is a photo of the harness:

 

[feralyouth]

@feralyouth , one thing you may want to check is the wire harness that connects to the oil pressure guage. The harness is in the right front engine bay. At end there are three branches: one branch connects to the AC pump and the other two are on the oil pressure gauge on the passenger engine tucked up a little behind an exhaust manifold. The other end clips to a connector on the passenger wheel well. It is just those 4 clips and is only about 2 feet long. It is very easy to remove and inspect. I had this happen recently and found that one of the wires had broken near the connector. I just re-connected it at the plug and it works again. Here is a link to other posts that helped me.

Oil Pressure Gauge FIX

Well, like many on here, I’ve experienced the dead oil pressure gauge in the dash of my 80. While most would probably say, “replace the gauge and move on”, I am really cheap, and felt like taking the dash apart… Cliff notes: I ended up bending the gauge internals to get it to read again...

forum.ih8mud.com

Right on I will look into that. I did move the wires to install a secondary battery and compressor over a year ago, so maybe it finally snapped.

 

[JoeCova]

Gauge movement is more important than position, the gauge and sender go bad over time.