markwhite
NAXJA Forum User
- Location
- Johnson City, TN
I just did a full tear down of the 1990 4.0 and got it back together. I changed the rear main seal, valve cover, front main, timing cover gasket, filter adapter O-rings, and the oil pan gasket. I get it back together and fire it up to check for leaks and no oil pressure...I shut it off immediately, but I wasn't sure if I damaged the oil pressure switch. I unscrewed the filter and it was dry. I even followed the instructions to prime the oil pump with a flat blade drill bit, a bunch of extensions, and a power drill. I know I'm gonna have to pull the junk back apart and put in a new oil pump. I don't think I damaged the bearings everything inside the engine had Lucas on it and I have had plenty of luck before with a vehicle being part a while and everything still been lubricated weeks and even months later. I got a rebuild kit for the oil pump when I had everything apart, what my question is: There was a spring loaded valve that looked like a tear drop inside and was held in place by a retainer pin. It was a really tight squeeze getting the new tear drop piece in place and the plate that rests on the retainer pin. If those parts were a few thousands of an inch off, and fit to tight to move, could it cause the pump not to get oil up to the filter? I assume it pulls the oil up when the shaft rotates, then the valve closes sealing the pump so as it rotates, it pushes oil up and out of the pump, is that how the oil pump works? Or is the valve on the spring just serve as an anti-drainback valve to hold oil in the pump when you turn the vehicle off? It is 1990 XJ with a 4.0.