Hey all I am new to this site, I recently bought a 2002 F-150 5.4L with 130000 miles and when purchasing this truck i didn't hear any type of knock or tick from the motor. after about 500 miles im starting to hear a knock from the bottom end. after reading other forums on the net people say it usually goes away after a few minutes after start up but this knock is always there, it kind of sounds like a diesel when idling, anyone know what might be the problem? could a different oil weight fix this? it has castrol syntec 5w20 in it at the moment

 

Welcome to the site.

Did you check your exhaust manifold? They can make the same kind of sound when a stud rusts off or they leak.

 

I have an 02 FX4 with the same issue. I have not tried to troubleshoot yet, but am leaning towards maybe a loud oil pump or something like that.

When I am underneath the truck an put my ear to the pan it is incredibly loud and sounds just like a diesel engine.

Let me know what you find.

 

Welcome to the site!

Mine does it to, some of the 5.4s are "talkers". They sound like a diesel when idling and run perfectly fine.

 

My 4.6 had a similar noise also. Had 230k miles on the motor and it talked when cold.

 

****s and giggs....try a full tank of high octane and see if it goes away...

 

Will not make any difference in the noise. I use a tuner and run high octane. Zero difference.

 

works for me. if i use regular theres a knock and ping. if i use premium its silent.