For the first 3000 miles on this new motor I have had 40psi at idle and up from there. Now out of no where I'm getting 20 and below at idle. When it's cold first thing in the morning I'm at 40psi. Then a quick trip to take my son to school it dropped to 20psi. On the way home it dipped into the teens and below when I turn or slow to to stop. But it's erratic, it rises with rpm but if you hit a bump or turn just right it goes up. When you first hit the brakes it rises then drops. Pulling into my drive way which is slighty inclined it drops even further. Enough that the DIC dings and says low oil pressure.

Is the pump going bad? Maybe a pickup O ring or something? At first I thought the oil was just ready to be changed. The rotella when it hits 3000 it starts to burn and oil pressure has always decreased some in all my turbo motors. I changed it out just to be sure and oil pressure is still acting up.

 

Cut the oil filter open. If the motor is dying, you'll find bearing material and magnetic metal shavings in the filter pleats. Otherwise, check for loose oil pump pickup, stuck oil pump bypass or malfunctioning oil pressure sender/gauge system.

 

Good advice ,

Also since you did a motor swap make sure your engine harness isn't pinched , the sending unit is plugged in completely , hopefully it's just a short .

 

its not the harness i made sure of that when i installed it. i have my stock 5.3 sender i'm going to throw in it to see if that's it. i've been pondering this all day. i remember telling my wife that if we had oil pressure issues when we start the motor for the first time, to check the O ring. i cant remember why, i just remember it being a huge pita to install. everything has been great up to this. it just happened saturday then the next time it was driven was this morning. cold 40psi warms up and just starts dropping.

 

First thing to check is the oil and filter. Drain it and it will tell the story. If it is the bearings, you'll find gold flake when you unravel the filter

 

I don't know if there's brass/copper in those aluminum bearings. Oil pressure that falls like a rock when oil gets hot (but no noise) is usually cam or main bearings. Any of that should show up in the filter.

 

In what aluminum bearings?

 

Stock bi-metal main/rod bearings are silicon aluminum over steel. There is no copper alloy, unless he used aftermarket tri-metal bearings during the rebuild.

 

Oh I see. Good to know!

 

I used clevite H bearings. I do have some copper looking dust. What I can't figure out is why this would happen. It's the same crank and block. The only change was rods and pistons. It was balanced and the crank was polished. All clearances we with in factory specs. The cam bearings were replaced by the machine shop. I cleaned everything like I have every other motor I have built. I guess when it's your own motor nothing goes right.