Just Bought A Complete 6.0lq4 With 48.000 Miles,turn It On Runs Fine , No Knock,no Noise,just No Oil Pressure At Idle But On The Gas It Comes And Gos Down.put A New Sender And Same Thing.

 

first I would throw on a mechanical guage, then go from there.

I had an old truck given to me because the owner moved and couldnt fix the oil pressure problems. I found out the guy never changed the oil and it wound up clogging the oil pickup tube with crap.

other things that can cause this problem is a scored pump not picking up enough oil, or worn berings not retaning enough oil. if your mechanical guage says the same thing i would up the thickness of the oil to something like 20w50 and will work as a temp fix for the scored pump or worn berings.

so start with the mechanical guage, then start looking into at least a partial tear down.

and if you just bought the motor i would try to contact the seller to see if your gettin screwed.

 

my rebuilt 6.0 has very low pressure At idle vs where it started, I was told cam bearings or pump. I will be buying a new pump soon and hoping for the best.

 

cam bearings are common for going out on gen 3 motors, it happened to my first one in my ss , factory warranty covered that one for me.

 

put an ls6 oil pump in and all should be fine.