Hello everyone. I have a 2004 Chevy Tahoe Z71 with a 5.3 liter V8 flex fuel, I am the original owner and currently have 168,142 miles on it. I have always used Mobil full synthetic 5W-30 with a Mobil oil filter. Lately I have noticed that on start up my oil pressure will read around 40-45 psi, while driving on the freeway, the oil pressure is between 50-60 psi. After a 30 or so minute drive at 75-80 mph, I turn off the freeway and once I hit city streets my oil pressure while driving will around 40psi, but my concern is when I am at a stoplight my oil pressure drops to 25-30 psi on the dash gauge.
Could this be just an oil pressure sending unit, or the dreaded O-ring on the oil pick up tube starting to fail? What would be the best way troubleshoot the issue?
Thanks
Mike
25-30 psi at idle doesn't sound bad to me at all, especially after being warmed up, especially at that mileage. If you want it to be higher, add some Lucas Oil Stabilizer on your nest oil change.
A quick internet search says for that on a warmed-up 5.3 V8 you should expect 20-30 psi at idle and 45-70 psi while driving so I'd say you're in safe territory. (Oil pressure varies with RPMs.)
Also be aware that oil pressure sending units are notorious for giving inaccurate readings. If an oil pressure issue is suspected it should always be verified with a mechanical gauge.
