I have a 90 4runner with a 3.0 and I need some expertise. I might should mention it has 300,000 miles showing. I havent had it long, and I am not sure it has ever had an overhaul, but there is that possibility. When I crank and run the engine, it appears.according to the gauge. to have good oil pressure. Then when it warms up the pressure reading goes to s---. I hear no unusual noise, and it runs good, just hardly no pressure reading. Anyone have any ideas as to why this might be doing this.

 

needs a rebuild/oil pump replacement

 

Just drive it.

I've been running 20W50 for 7 years and 120,000 miles. (current milage is 265,000) This gets the oil pressure to read in the normal range at normal temperatures. It might only make me feel better and I might have insufficient oil volume for proper lubrication, but is has been good enough for 120,000 miles so it can't be TOO bad.

 

vote for drive untill rebuild.

 

I held a 20r at 7000 rpm for 8 minutes straight with NO oil pressure before rocker arm failure

when I disassembled the motor the bearings were still in GOOD shape

 

I would question the oil pressure sender. Unscrew it and try a new sender, or a pressure tester of some kind. I had low oil pressure readings too, and I swaped in a 2001 5VZFE with only 27,000 miles and I still have the same pressure readings. I'm using the same sender as before so it must be the sender or the gauge, cause I know it's not the engine.

 

x2 on the sender being incorrect. Before you junk the motor, hook up a nice oil pressure guage directly to the engine and see what ya get. Although with 300k its possible that your bearings are getting a little worn.

 

Thank all of you guys for your responses. This is a deer lease vehicle. I think I might try a sending unit or go to a mechanial gauge. If that doesn't fix, then I will drive it till it pops.

 

my 3.0 reads bout 3/4 the way at idle when warm, and half when driving, is that about normal? it drives great.

 

Are you saying it reads higher at idle than driving?

 

my 95 4runner with a 3.0 will stay at about 1/2 goin 65. at idle it'll go down to about 1/6. it has 160,000 miles and i use 10w30 castrol high mileage. i hope its normal. I drive it like that all over florida and it hasnt let me down yet. I would definatley put 20w50 high mileage if its not the gauge, and give that a try. at 300,000 it could be gettin ready to croak. save some money for a rebuild.

 

Yeah that's about what mine does too, even after replacing the engine. I think it's the sender on mine.

 

My gage read low from 35,000 to 190,000miles do not know why but it was never an issue until the gage or sensor or something went bad. I still have no engine problems but I do not have a reading at all

 

Don't trust the factory gauge. It annoys me that there is full instrumentation on my truck but none of my gauges have actual numbers on them. I'd love to know what temp the engine is or how the alternator is doing.

 

I second that and if in doubt measure with a analog old style meter with adapter instead of the sending unit , if the second meter agree's then I would say find out why before you need to replace rods or line bore your mains
And I have to ask.............have you checked your oil

 

OK so if you wanna know mine, it's 1/4 at idle and goes to 1/2 at 1500rpm or above.. I too was worried about idle pressure, but I guess it's ok

 

Right around a quarter is good if your running 5/10w30w , and up near or just over half for 1500rpm or so is fine as well .

 

Yeah I can now say the factory temp gauge on my truck stays smack dab in the middle all the way up to 235 F. If your factory temp gauge ever shows the slightest bit hot take action quickly because you are most likely over 240.

 

mine always looks like it has no pressure, but if you rev it up just a little bit you will notice the oil pressure indicator rise as well. I believe this is just common to Toyotas. My brothers 22R did the exact same thing.

 

If you read in the owners manual, it will tell you that at idle the oil pressure will read super low, like 4psi.

I'm sure that your oil pressure comes up at higher RPMS, your sender might just be sluggish. Does it ever come up when you're running higher RPMS for an extended time, like a few minutes on the highway?