Got a 2003 Expedition with the 4.6 Liter engine.
About 3 weeks ago, the car started making some rattling noises but thinking it was a pulley or something, I ignored it.

Now, coming home one day, the light "Low Oil Pressure/High Temp" went on and the gauge pegged all the way down. Drove it light that for about a mile.

Starting up the car, the pressure gauge stays in the middle, but at about a mile of driving, the light goes on again and the gauge pegs down. The rattling noise (sounds like somewhere where the pulleys are) continues at idle.

Any info about what this could be would be greatly appreciated. Also, how can I start diagnosing what the problem is ? Is taking off the oil pan the first thing I should do ??

 

This sounds like your timing chain tensioners and guides have come apart and the plastic from them is at the bottom of your oil pan blocking the oil pump pick up.

Stop driving it until you get this fixed!

 

Is it safe to drive without the tensioners for a bit if I remove the pan and clean out the pick up ?
How much of a pain is it to replace them myself?
What would a dealer usually charge to do that for me ?

Thanks for the quick reply.

 

If it were me I would drop the oil pan and look for plastic in it. If you find plastic you know for sure it's the tensioners.

The problem is these motors are interference motors. If the timing chain were to jump you will wipe out at least the valves. And ther is a real possibility of severe piston damage. I personally wouldn't drive it unless you are OK with the possibility of having to pony up for a new motor.

Replacing the chains is kind of an extensive job. Here is a thread with a video in it on how it is done. What you see in the video is slightly different than what you will see under the hood but it will make sense.

How To Replace the Timing Chain on a '97 4.6L - Ford Truck Club Forum

I don't know what a mechanic would charge for the job.

 

Do I have to drop the front axle for the oil pan removal or hoist the engine up ?

 

I don't know on that one. Mine is 2wd. Others will probably chime in. Just give them a little time.

 

All day wasted for nothing. Tried to remove the pan, got the cross-member off by cutting the bolts off - nightmare. Then tried to get the pan off but the 4 WD setup prevented the pan from coming off. Now stuck with an unbolted pan dangling in the air with no way to get it off.

Anyone know what next, let me know. Kinda dead so far.

 

You have to disconnect and lower the front axle assembly to get enough clearance. Don't forget the oil pickup is all the way down at the bottom of the pan. That pickup keeps you from being able to slide the pan to the side. The only way to remove it is to drop it down enough to clear the oil pickup.

The other method is to remove the intake manifold and either the radiator fan or shroud. Then you can lift the engine enough to give you the needed clearance. This method is the better choice if you have another reason to remove the intake, such as a vacuum or coolant leak. Then you get to kill 2 birds with one stone.