Fviehman91

I have a 91 f150 with a 92 300 in it. The first engine blew a head gasket because the guy before me had no idea what maintenance was. Once I put the (new engine in it ran great for about 500 miles then it had a sudden drop in oil pressure. First i thought it was just the sensor going bad so I put on a true oil pressure gauge. And still when the engine was running for about 30 minutes the pressure would drop to around 15psi. So i pulled the pan and saw a whole bunch of sludge sitting in it from sitting in the junkyard for awhile so I clean it all out, replace the oil pump, pick up tube. And pulled the valve cover and clean a tiny bit more sludge from the head. Ran a thinker oil (10-40) through the engine for a few hundred miles and did an oil change and saw a bit more sludge in the filter, so I dropped the pan one more time and got all of that out. Repeated the process one more time but found no more sludge. Engine still had low pressure after about 30 minutes. I have no idea what else could be the problem. ( and before anyone says it, YES I do have enough oil in the engine)

Fviehman91

Just an update on this thread in case anyone has the same problem. The mains are wore and I'm pretty sure that is what the problem is coming from. Almost done rebuilding the bottom end. Once I get the engine back in the truck I will post my findings.

Chris_1

iTrader: (1)

An important thing too is to make sure the oil drain holes are clear. You have some in your heads and some in your lifter galley. If they get plugged up with sludge you can end up with the oil that gets pumped up not getting back down to the pan fast enough.
Once you get things back together (and you might be able to check most of those holes and ensure they're reasonably clear from underneath while the pan's off) it might be a good idea to run some Seafoam engine treatment in it to help clear up some of the sludge you can't see.

Myron's

How did this go?
Did you get your oil pressure back?