HI, I HOPE YOU ALL CAN HELP ME WITH THIS, I GOT A F-150 X CAB WITH 165.000 MILES, AND THE ENGINE HAS A NOISE VERY SIMILAR TO THE DIESEL ENGINES BUT SMOOTHER.

WHAT COULD IT BE?
THANKS

 

It may be a crank bearing starting to go , a broken valve spring or some piston slap. Try putting a screwdriver to different parts of the engine to find out where the noise is the loudest and maybe check the plugs and compession to startwith.

Does the noise get louder or change pitch when you're driving?
Did it start all of sudden?
Are you lossing power?

 

the 4.6's have a "dieseling" sound at times i think it is heard most when the truck is idling. Have a mechanic listen to it....if its running right, keep on driving!

 

the sound it's always the same, it doesn't get louder.
i don't losse any power and the noise started of sudden.
im gonna try to find out where te noise is coming from.
thanks guys.