F-150 Oil Pressure

I am looking at a 1999 Ford F-150 that has no oil pressure. The current owner was driving driving on the highway and the oil pressure dropped off. He stopped and had it towed home. It still runs, but he says it runs ‘odd’ now. I’m thinking its the oil pump… any other ideas? The pump is $56 form rock auto, and the truck is $1200… is it worth the gamble?

Low oil pressure can be caused from other things other than a worn oil pump. If the rod/main bearings have excessive clearances this will also cause low oil pressure. So it may just be a matter of a bad oil pump. Or the engine requires a complete rebuild because of worn bearings


Change the oil filter, remove the spark plugs so the engine won’t start while it spins freely, install a mechanical gauge and crank the engine. You must operate the starter long enough to fill the filter before pressure can move the gauge. If even 10psi can be achieved this way it is likely the engine is mechanically sound enough to start and look for the pressure to reach 50+psi. The gauge is a phony. It’s actually just an idiot light.

The oil pump is the first thing to see oil in the lubrication system so if things are bad enough that the pump is trashed then it stands to reason the engine that it feeds is in even worse condition.

You can safely figure on a new motor and 1200 is too much unless the truck is very clean and you can do an engine rebuild or swap yourself.

So I suppose this engine is probably full of clean oil at the moment? Topping the oil off is usually someone’s first step when they realize they screwed up and ran it empty.

If it’s a $1200 crap shoot leave it alone as ok4450 recommends.

I am sorry but lost oil pressure, does not run right = toasted engine. RUN RUN RUN!

These vehicles use a simple on/off type oil pressure switch to make the gauge work. The needle on the gauge never moves other than mid-range and zero. The switch should be located near the oil filter. I would replace it and see if that restores gauge function…

What engine is installed in the truck? Mileage?

No !

No?? Is the V8 F-150 different than a Vic? They have an “oil pressure gauge” but it’s phony. It does not read pressure. Just yes or no…

Will the $1,200 price allow you to spend the money to replace the engine and still be under book value of the truck?

The chances that the motor is damaged is 100% How much is the engine damaged is the question? You might be able to get it running and get a few years and miles out of it. If your plan is to use this truck very little it might last awhile. If you plan to drive it daily on a 30 mile commute better figure on a new motor sometime soon.

Go to Edmunds.com to see the “true market value” for the truck.