Howdy,
I have a 2005 V6 4runner with the 1GR-FE 4.0 liter engine with 203,000 miles of. A couple weeks ago I was driving and the oil light turned on. I was close to home so drove for 1/4 mile and coasted in with engine off. Took it to a shop and they told me that it probably had a bad pump. The reason they gave me was that when it is started it is >40 PSI but dropped to 13 PSI at operating temp. I checked the pressure myself and it went from 60 PSI down to 10 as they said. I found the maintenance manual and for the 1GR-FE it says the pressure is supposed to do that. At 3000 RPM it is supposed to be 43psi - 85psi. At Idle it is supposed to be >4.3psi. Mine was 40-45 @ 3000 and dropped to 5-10 @ idle. I don't think I'll be using that shop again. Can anyone confirm that this is normal. I heard that the Oil switch is just an "idiot light" if the psi drops below 2.5. Should I be concerned? Any recommendations? Should I install a digital gage for the pressure?
Thanks
-MBB
Since you checked the actual pressure and it's within specification I would just replace the 18-year-old oil pressure sending unit.
The red ‘engine oil’ light came ON on my 2000 Acura Integra last year and the oil level and oil pressure were fine. It turned out to be a bad oil pressure sensing unit.
Update**
I called the shop and let them know my concerns and they said that the readings they were getting were when the engine was "under load" and that it shouldn't drop like that. When I checked my pressure it was just in neutral. Not sure if they are just blowing smoke.
-MBB