I have a 2004 f150 with the 5.6 engine. It has ahad a knocking noise coming from the engine since I bought it in 06, I have been told it was a nylon gear on the oil pump drive, I lost oil pressure and stopped the engine. Loaded on a trailer and brought it home. Upon loading it the oil pressure came back up and engine sounds and runs fine. I think the oil pump drive may have stripped. I would like to find an exploded view of the engine. Any help is appreceated

SOURCE: ford focus turbo diesel low oil pressure with no knocks from engine

Possible oil sending unit problem.

SOURCE: oil light flashing/engine knocking

you are abouot to lose the motor,,,,you have a rod knocking when you start it up and an oil pump wont help it been there done that all it does it make it worse

Harvey N Tawatao

• 3854 Answers
• Posted on May 29, 2009

SOURCE: oil pressure problem

You oil pressure sending unit has gone bad, it's common to go bad and some even leak oil. 
The oil pressure sensor is on the back of the block on the passenger side, you can get to it from the top and not from the bottom. There are (2) switches back there that screw in to the block and you can only see it from the top of the engine. The Oil Pressure Sending Unit is the one wire harness with a green and white strip on it. The other switch has more wires to it. 
When you pick up the new sensor, make sure you get the right one. make sure you get the Oil Pressure Sending Unit which sends variable oil pressure and has only one quick connect for the wire connector. The oil pressure switch is the one that only activates the oil light on older engine. 
Once you get the right part at Auto Zone for around $9.00, disconnect the wire clip with the green with white strip on it. and use a deep spark plug socket with a extension and u joint to get the sensor out. The sensor comes with teflon tape already and no oil should leak out from the block. It as simple as replacing a bolt and reconnecting the wire connector. 
Good luck and hope this helps, take no more then 10 min to do but about 5 hours for the engine to cool off LOL

SOURCE: replace oil pump on 2004 f150 fx4 5.4l

Remove the oil pan and replace the oil pump.

Ginko

• 19396 Answers
• Posted on Sep 12, 2010

SOURCE: Ford Freestar 2004, 3.9L V6,

Hi.

If by clicking noise you mean typical knocking coming from the engine, that is caused either by valve problem or by a bad knock sensor.

I suggest driving to nearest garage and doing an OBDII code scanning, then coming back to us with the codes.

The scan is done for free at the nearest Autozone, or can be done at any garage for a small fee.