My gal has a 93 Forerunner that when first started has perfect oil pressure but after running at operating temp for a while looses most of the oil pressure and drops below the low "acceptable" range even at high rpms and drops almost completely off at idle. Obviously I have made sure the oil level is appropriate. What's going on? Bad pump? It has 185k on the odo. Any of you 4runner gurus experience this?
1st thing I would do is consult the owners manual....I know, I know, whats that? and, yeah the thing you'll have to blow the dust off of to read....
I have a friend that went through the same thing, "it aint got NO oil pressure" well, clearly described in the manual it was where it was supposed to be....
he wanted me to rebuild the motor couse of this... good thing I looked...
once toys are warm, at idle they resemble no oil pressure
There seems to be no correlation in this case, I realize than hot oil is less viscous and that cold oil is "thicker" but this oil pressure reads both very low and middle of the road both at operating temp. (middle) furthermore, I would assume that higher rpms would raise oil pressure due to the dizzy running the oil pump (doesn't it in the 4runner's case?) In this truck, sometimes thats the case and sometimes it's not.
Thinner oil like 5W30 will also give lower readings. Try a thicker oil. Those OEM gauges are fickle. I've had three boneyard gauges in my truck (because of bad temp gauges) and they all read different. Get an aftermarket gauge and call it a day.
Thinner oil like 5W30 will also give lower readings. Try a thicker oil. Those OEM gauges are fickle. I've had three boneyard gauges in my truck (because of bad temp gauges) and they all read different. Get an aftermarket gauge and call it a day.
I had this problem last summer, was running 10W30 Valvoline. As I approached each oil change the needle would hover closer to "L". Never had any issues from insufficient oil pressure but I think I found the cause. The Slo has an oil cooler on the driver's side of the block and mine was dirty as sin (short cylinder shape w/line to it). I sprayed it down with Simple Green a few times at the car wash to clean things up. My oil wasn't horrible but I think it was breaking down faster due to running on the hot side. Before I cleaned the cooler it stayed at the mark before the "L" consistently for about 1,000 miles. However I threw a wrench in the experiment and went whole hog on synthetic at the same time. Weather it was cleaning the cooler or switching oil now it's always at the "L" at idle.
good thing I looked...
