Ok so a few months back my oil pressure started going down. At idle it was right above the red and cruising is was between 10-20 psi. I changed the oil sending unit, didnt fix it. Put 20w-50 oil in it, help alittle but its not where it use to be. When i WOT it it will go to about 40psi than drop than all of a sudden back down to 20 and than slowly build back pressure. I have also noticed that it has a leak now. There is oil on the bottom of the motor and trans. Not alot I was about 1/2 quart low when a changed my oil. So what could it be?

 

put a new gauge on it...they are just like a piece of film and it stretches and the gauge will go lower and lower...
as for it droping at wot...do you run a big filter? i do and i run normally 6-6.5quarts. with a stock filter i think the pan needs 6 quarts...

 

I use the ACdelco 454 filter with 5 quarts, thats the way ive always ran it and its been just fine.

 

What is the mileage?

 

Probably needs a rebuild. Low pressure could mean the bearing gaps are widening up. Check for metal shavings in your oil.

 

5 qt with the big filter is definately low...id add another qt and then see if it drops at wot..

 

Our oil pump pickups like to fall off too (stock ones that arent welded in place), that could be your problem.

 

The 454 AC filter (a shortie) has recently undergone reengineering by the cost cutters. It would be worth your while to carefully cut the filter open and make sure that the packing hasn't collapsed and clogged the passages and resricted an adequate supply of oil. I'd do this before driving the car much more. We've lost bearings in the past due to collapsing oil filters. They seem to have a greater tendency to fail on startup in cold weather when the oil is thickest.

 

I've never heard of an oil pump pickup falling off a stock SBC where the pickup hadn't been messed with before hand. If his pan has never been off then theres no reason the pickup should fall off, at all.

 

The mileage is 150,000. I changed the oil filter a couple of times and have tried different types i.e. fram and acdelco, and the 454 is the smaller filter and i believe it can only hold 5 quarts i could be worng though. My car still runs great just like before the pressure drop. Could my motor just be wearing out?

 

YES!

 

Yeah the motor is just wearing out. Bearing clearances are bigger due to wear. Eventually the motor will kick a bearing due to lack of oil between the bearing surfaces. That's what happened to me.

Mikey