I have a 1998 suburban and I just replaced the head gaskets it had alot of water and sludge in the pan and the intake valley, it started up ran great drove it on the freeway ran good oil pressure was normal 40 then all of a sudden the engine cuts off. pulled over turned it back on started to make a rattleing noise/ knock drove it and it went away but the idle is very low and the oil pressure is running about 20 then I got closer to home and it started to knock check gauges lite came pressure was very low as I was at a stop then I press the gas oil pressure goes close to 15. checked the oil and it was exteremly hot! and oil changed to a grayish color it had a little sparkle to it i think it has some metal particles, I ran 10-40 in it has about 120k on it. I looked at my rad and it has connections for a oil cooler lines and I looked at the oil filter where there should be lines and there wasn't any they had plugs on the oil filter mount, did they come this way?

 

Welcome to the forum. Had it been driven w/ the water and sludge in the crankcase? If so, then your bearings are most likely gone as water is a lousy lubricant.