Not sure if you could test the oil passenges.
You could always flush the engine and see if that does anything.
What brand/type of oil are you running and what grade ?




Fred

 

I just checked the FSM for the 3.0 (which is what I have in my 4Runner) and:

Oil Pressure:
- At idle speed (normal operating temperature) -> 4.3 psi
- At 3000 rpm (normal operating temperature) -> 36 psi.


This is certainly in line from what I expected to see.

Hi pressure is not a good thing and usually/normally points to a problem.
Could be as simple as running an oil that's too thick.





Fred

 

I am running Castrol 10w30, which is the same that I have ran in my other Toyota for the last 100k miles. I am also running a genuine Toyota filter. I just added some Rislone in the oil, so I will see if that helps. It was slightly ticking when I bought it, mainly at idle, but now it is ticking a lot louder and can be heard throughout the RPMs. It seemed to get louder after I did an Italian tune-up.

 

"Oil pressure at idle speed is 4.3 psi (.3kg/cmsq) and 36-71 psi (2.5-5.0kgcmsq) at 3000 RPM"

Straight from Mitchell On Demand 5 in specs for 1988 toyota 22r pickup

 

The original question concerned oil pressure drop after climbing a hill. I speculate that the oil temp went up, the oil was thinner, and pressure dropped accordingly. Flow would have been greater at the higher temp. If you are intersted in science, I suppose you could install an oil temp gauge and correlate temperature, pressure, viscosity, etc. This is what the designers did when they developed the engine.

In some ways, this discussion falls into the category of too much data, not enough information.

 

Rislone is designed to clean hydraulic lifters which aren’t used in any of Toyota’s 4 cyls. It won't hurt anything to use it and it will clean any sludge that was once anywhere in the engine. However, Rislone nearly has the viscosity of water (really thin) so that may be why the engine is ticking a little louder. Rislone may have cleaned some debris in the valve train, causing a larger gap between the valve stem and rocker arm, causing the valves to sing a little louder. All you probably need to do is adjust the valves.

 

Riselone worked to fix a sticking valve in my other 22R Toyota, so I figured I would try it on this truck. It was ticking before I put the Riselone in, that is why I put it in. The valves were adjusted properly about 2000 miles before this starting happening, and I checked the valves from where the noise is coming from and they seem to be good. I plan to do some more checking tomorrow to try and figure this out.

 

You do need oil flow, but it is oil pressure that lubricates your bearings.

If you don't think so, take an engine apart and increase the oil clearances to about .010" and put it back together and test it. It will knock like crazy and won't last very long before it comes apart. this is becuase there is not enough oil pressure to resist the mechanical forces. I'm sure your flow would be more than double.

I'd be concerned about your drop in pressure after heavy load. It is true that your oil pressure will drop when the oil temp goes up, but driving only 1/4 mile before it comes back is not enough time for the oil temp to go back down. Keep an eye on that you may have a sticking oil pressure relief valve.

 

No, flow lubricates the engine. Increasing clearances until they are out of tolerance is, out of tolerance. The engine is designed to be lubicated within the capabilities of the oil film, and that determines the design clearances between the bearings.