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2011 AV with oiling system issue

dakotadog

Full Member
Joined
Mar 2, 2003
Messages
65
Location
Boston MA
OK so I have a strange issue going on with my truck.  2011 4wd with the standard 5.3L engine.  I have owned this since new and have always stayed on top of oil changes and maintenance.  The truck now has 130K miles    There seems to be plenty of oil pressure, no valve or lifter clatter, I replaced the valve cover and stopped losing oil, and finally had a mechanical gauge verify pressure

Here's what happens  Oil pressure stays fine for weeks, then suddenly as I'm driving the gauge drops slowly toward 0 and eventually the warning light comes on than the "ding of doom" goes off.  Sometimes I get a P0521 , sometimes not.  Sometimes restarting the engine resets the pressure on the gauge for a while, recently I have discovered that if I change the oil filter  (I usually use Delco) the issue goes away.      So here's what I have done so far as this has been an intermittent problem for years, but now it's happening at more frequent intervals.

So 3 years ago dealer replaces the oil pressure sender and screen,  a few weeks later - happens again and they replace the oil pump and sender again, while they are at it they add the baffle to the oil pan.    2 years ago get a consistent P0521 so I replace the sender and screen again - problem goes away.  6 months gap problem returns  intermittent p0521  so once again check wiring, replace sender and screen .  It's at this point I realize that an oil change "resets" the issue, my guess it's really the filter change.  I switched filter brands and it didn't seem to make a difference.  I am so frustrated with this and wanted to see if anyone had any ideas. 

So....  if it's electrical what would replacing the filter matter,  if it's a stuck bypass then why do I get the P0521? 
 
What filter are you replacing it with? I've read about the long filters losing less oil pressure whereas the shorter filter would see a drop in pressure and experience lifter tick.

Another item i've read that causes low oil pressure is the oil pickup tube oring. You'd have to remove the oil pan to get to it, which isn't as easy with 4x4.
 
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