I have a 94 f150 with a 4.9 Inline Six, 160k miles and having problems with oil pressure. The engine is on its second oil pump and is losing oil pressure once again. I have changed the oil religiously since I've owned it, second owner. The mechanic who replaced the pump told me to never use one of those flush systems or run anything but oil in it. I have heard that you can run a quart of Automatic Transmission Fluid in with an oil change to help clean out any sludge. Any thoughts. I'm thinking of dropping the oil pan and cleaning the pump but not sure of whats involved.

 

i had a probem like that once ,it turned out to be the cam bearings the were wore out enough to let the oil pass right on by , hi rpms would give me some pressure but not much , the only way i know how to fix it is to rebuild it sorry .

 

Are you sure it is the pump? Can you use a mechanical gauge and test the reading? Costs about 15 dollars to buy a cheap gauge and line, hook it up and test.

Justin

 

Do you have an aftermarket oil pressure gauge installed, or are you going by the factory gauge? The reason I ask is because the factory gauge in your truck is controlled by a switch, rather than a variable sending unit, and doesn't read varying pressure. It is either on or off. If it is the factory gauge that has you concerned because it's moving, or reading lower than you are used to, try replacing the sending unit, mounted on the drivers side of the block, to the rear of the distributor.

If you do have an aftermarket gauge installed, make sure the line isn't kinked, and that the fitting that goes into the block isn't obstructed with teflon tape, or sludge.

Take care,
~Chris