I need some advise regarding my oil pressure.
My 3.0 3vz appears to have lost oil pressure. At startup, the pressure is above mid range, but after driving on the freeway at 70mph for 20 minutes, the pressure drops to just above the low range indication per the dash gage.
At first, I noticed theis pressure drop with the oil change and installation of a fram extra guard filter. I though this filter was the cause as it probably had more pressure loss since it probably had more filtering element to push oil through. However, I changed the oil last night and this time installed a toyota brand filter and to my dismay, the pressure continues to be low.
This low pressure seems to have cropped up at the same time I had a cooling system leak, external to the engine. I just replaced the darn bypass pipe that had a pin hole in it. (major pain job to get to that thing)
During the bypass pipe work I put in a new timing belt, new idlers, new radiator, new fluid coupling, new water pump, new thermostat, overhauls ps pump, plugs and new belts.
My coolant was shot and parts of the old seal material were floating in the radiator. Rust was present. Could the oil cooler be clogged and not cooling? Could that cause a pressure drop when driving a while?
Both before the problem, during and after repairs, the engine has run smooth and strong and always has.

I had the head gasket replaced under warranty as preventive maintenance during the toyota "head gasket campaign" (recall). The oil and coolant are clear.

Related details:
93 Pickup, 4wd ex cab. 3.0 V6 3vz
miles: 206k
Oil change interval: never more than 5k between changes.
Mostly pavement driving
I'm running Mobil 1, 10w-30 and have been for the last 3 years.

I hope this paints the picture and that someone can provide some insight into what might be causing my pressure drop. Could it be a clogged oil cooler? Could the oil pump be worn out? Could the gage or sender be out of calibration? Or is it worse.. bearnings?

Thank you,
Kevin

 

I bought my 2nd Gen 3.0 from the original owner who took very good care of it (and had the paperwork to back it up). My oil pressure has always been on the low side and I am beginning to think the gage is either reading wrong or the scale is not calibrated the way we assume it is.

When I first start in the morning it will go almost to the third mark
After it warms up, it will read just a little bit above the first mark @ 2000 RPM
When it idles, it dips half way below the first mark and the beginning of the scale @ 750rpm

I have done a full tune up, O2 sensor replacement and complete fluid flush (engine, tranny and differential) including Auto-RX for the engine and a switch to Mobil1 synthetic oil and Toyota filters all the way around. It runs just like new and doesn't use any oil between changes but the pressure still reads lower than I would expect.

I did a lot of research and this seems to be sort of a common issue with 3.0 and I wasn't able to find anybody that resolved it or had problems by it.

I think I will get a true mechanical oil pressure gage hooked up and see what it is really reading - for all I know the gage could begin the scale @ 20 psi and the high side is 80 (not likely I know...)

 

Thank you for the detailed information.
Your description regarding where the pressure gage is during your start and warm up and reving is very similar to what I get now. It used to be that at freeway speeds of 70 mph(3,000 rpm), I would have the oil pressure centered on the gage, this would be between the first line and the second line. Now, at 70mph(3,000 rpm) the gage is reading about 1/3, just a bit over the first line, which is supposed to be the lower limit line for operation at speed. That's why I'm a bit concerned.

 

If you strictly go by the owners manual it is normal to drop into the low range at idle. Anything above the line is "normal operating range" and anything over is excessive. I have contemplated putting in a mechanical guage, but I think that would only make me more concerened since the normal range seems to fluctuate considerably. My J**p had a mechanical in it. It really needed one. The old AMC motors were notorious for dropping pressure suddenly. It was all good until the pressure line split when my wife in one of business suits, was driving it. Long story short, Jeep was sold to get parted out, I have a Toyota now. And they lived happily ever after. That was only one of that vehicles transgressions. It really hated my wife.

I have digressed from the subject.

 

Your readings sound normal. I now run 0w40 since my truck has 160k and I see 100+ temperatures throughout the summer.

 

Another vote for 'that's normal'. My 1993 V6 4runner with 203,000 is exactly the same. I've tried 10W40 and that high mileage oil but it didn't make any difference.

 

mine does the same with amsoil....another vote for its normal. I guess as long as it rises when given throttle, its ok.

 

I'm glad to see that it's a common problem...., I put about 1/2 quart in a month. I have no smoke just likes to drink oil I guess. I run 10w30 but I think my next change will be 10w40.

 

Yet another vote for normal, mine does it also.

 

Its normal readings, its not a problem. 5-8 psi at warm idle.

 

The oil pressure is normal and nothing to worry about. The 3VZ pretty much doesn't need ˟˟˟˟ for oil pressure to stay alive, it just needs oil in the crankcase. I've seen brand new shortblocks put off about 2 psi at idle and read "low" while on the highway. If it has oil in it and isn't knocking then I wouldn't worry about it.

 

I have a '93 2WD 3.0 with 143,000 miles on it. Back around 80,000 miles I noticed that warm / at speed the oil pressure indicator was dropping below the '75%' (top end of midrange) mark where it'd always stayed nailed. I had it tested and was told the only definite change was some sensor fatigue. I had the sensor replaced (I'm a stickler for instrumentation reliability). Once again, the indicator needle stayed nailed on the boundary between midrange and excessive. Now it's fading again. On start-up, it climbs right back to the usual top-of-midrange mark. During long stretches of expressway speeds it'll drop down to no lower than 80% of total gauge span - still above halfway. The engine essentially uses no oil whatsoever (but then it's been weaned and fed on Mobil 1). I quite worrying about the indicator dropping down into the 'bottom' / 'deficient' range when warm at idle (e.g., stoplights).

Bottom Line: Yours seems to read lower than mine, but what you're seeing is 'normal' for my experience.

 

Another vote for normal. Mine seems to be running in the same range as everyone elses.

 

Thanks to all for the feedback. I'll commute with a little less stress.

This weekend its time to check the valve shims.

 

Here's some input to buck the trend...

Mine ('95) ran a little low from the time I bought it with 57,000 miles on it. Blew the head gasket and replaced the engine at around 96,000 miles, and the shop that did it was less than competant. They never even looked at the oil pump which is an item I assumed would be replaced with the swap of a remanufactured long block. They pulled and used the one from my old engine.

Long story short, that engine also ran low oil pressure from the git-go and I noticed it crept lower at highway speeds over the next several months. In May, while driving home from a long road trip, I noticed the oil pressure was barely registering, followed by some loud ticking from the engine, followed by a loud "BANG". The oil pump had failed and I gernaded the engine.

I haven't heard of anyone else having an oil pump fail, and my circumstances are likely not typical or even similar to those you're experiencing, but I'd recommend you keep an eye on that pressure and maybe even get the oil pumped checked. And fer gawds sake -- pull over if you hear a loud ticking. :pat:

Ed

 

Sad to hear that. I'll certainly never stop watching the gage.
I've noticed that it takes about 20 minutes of fast driving to get the pressure to drop. I suspect the oil temp rises much more slowly than the coolant temp, thus the oil pressure doesnt reach equilibrium when the coolant temperature does... but rather 15 minutes later.

Aside, if you have a '95, which engine is in it? A 2.7 or a 3.4 or ? I suspect the 3.4 is very similar to the 3.0.

 

Nope -- '95 was the last year for the 2nd gen 4Runners. Mine has the notorious 3VZ-E like yours.

 

How many people have low oil pressure and aren't running a stock toyota oil filter?
My oil pressure was low even on a rebuilt motor with a new oil pump. Happened to be using fram tough guard oil filters that have the bypass supposedly.
I decided for grins to go back to the stock one and my oil pressure came up now it's alot better than it was and the oil pressure gauge seems to move more quickly now when on the throttle. Just proves once again don't use aftermarket oil filters and stuff on your toyota because they will likely cause damage to your engine. I am surprized no one has sued fram yet over this. What makes things worse is the stupid fram filter actually costs more than the stock toyota one.
I honestly think FRAM FILTERS are CRAP now my yota won't ever see one again.

 

Glad to hear this is normal, cuz my truck does the same thing.

 

You can check this site out it's basically one guys review on several types of oil filters:
http://minimopar.knizefamily.net/oilfilters.html

Fram extra guard:
I would have sued thier ass if it happened to me.


Fram double guard:
I think if any folks have inccured damages from Fram oil filters Fram is likely paying them off and having them sign a gag order so they don't discuss it. I did a big search to find lawsuits I did find one against fram from purolator about a design theft or something. I found also another one on Acura forum after changing the oil the fram oil filter seal failed (came unglued from the filter) on his NSX it almost cost him his engine. They may have been good in the past and maybe thier top end is ok but this is my opinion on them.