Hey everyone, great forum. I just got a 88 Grand Wagoneer with a 360 for free because the guy said the motor was shot and had no oil pressure. Well I started it up and played around with it and at start up it had about 80psi and after about a minute or so it dropped to around 40psi, then after another minute or two it dropped to about 10psi, all the while the engine still hadnt reached normal operating temp, only about 110 degrees, so naturally I saw the drop in pressure and heard the enegine start to make a little bit of noise, I shut it down, and just for the heck of it I started it right back up not even 30 seconds after shut down, and I looked at the pressure guage and it was right back at 80psi again, now it doesnt matter if it is warmed up or not, it almost always does this. Do you think I might have crud in the oil returns in the heads and the oil isnt coming back into the pan quik enough, or maybee my pick up is clogged, or could this be some kind of common problem with these trucks?? I am going to pop the valve covers off tomorrow and start digging in, I hope I will be going in the right direction.
Thanks in advance everyone, Jack
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I would look at the oil filter adaptor and sending unit first. Occasionally the plunger will stick if it has worn a groove or if oil has sat behind it and thickened. Take the large 7/8 bolt off the oil filter adaptor and take the spring and plunger out.....if you can. clean them and re-install and check the pressure once again.
I inspected it and cleaned it up a little bit, and then I realized that it was in backwards (I think) The spring was in first and the plunger was kinda in the seat of the 7/8 bolt. So I put it together the way I thought made more sense, and started the truck and the oil pressure gauge was pinned over 80lbs, and the valvetrain was nice and quiet. I let it run for about an hour or so, revved it up a few times and the pressure never dropped below 60lbs, and when I hit the gas the pressure went up. So I am guessing I solved the problem?? I will put it on the road next week and begin driving it so i will see if it is gonna work out, now all I have to do is figure out why my tailgate window won't roll up and down.
I am happy for you...nice find!
I just ain't right 
