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 doubt that sludge is your problem. Since you've already changed the pump once, you must have already dropped the pan and cleaned all the crap that ends up down there. The stock cam timing gear ususally 'sheds' it's nylon gear coverings and it all ends up in the bottom of the pan. Usually, not a problem, as it's very large pieces and the oil pump screen stops it all, but could cause a blockage problem.

The only way sludge could form that quickly is if you do lots of short trip driving, where the engine does not reach full temp. Then, I guess you could run into sludge buildup quicker.

My guess it's just your main / rod / cam bearings have just gotten bigger 'gaps' in them. Takes more oil to fill them, taking away the pressure.

What weight oil do you use? Maybe try a 10w40 and see if that helps with the pressure. Might even go to a 15w40 if it's available.

Dropping the pan will usually require lifting the motor. If you are lucky, you only have to un bolt the motor mounts and then lift it up by the bell housing. You might have to remove some hoses, some additional stuff on top, and at the worst, have to lift the motor out to get to it.

Good luck!

 

Right now I'm using 10w30 Quaker State. Will try different weight this evening. Just went out and started it up, when the weather is warm the oil pressure comes up just fine. Seems to not like the cold weather. However it still has the ticking sound even though the oil pressure is up.