I have an 04 5.4l triton. It has done the start up rattle thing since 5K on the clock, I'm now at 90K. Now it has started to make this terrible rattle in the front of the engine when starting. It sounds like metal nuts in a drier. There is no uniformed clicking or any kind of rhythum to the rattle. It is completely random, and increases slightly when you bring the revs up. It only does this for 10-30 sec after start and then goes away. It seems to do it more often when the engine is hot and then restarted. Once the rattling goes away the engine is as quite as can be, it never comes back while engine is running. I had the dealer look at it and they gave the standard answer of cam phasers. I don't belive them as the noise goes away and then the engine just purs. There is no loss of power or anything that suggests internal parts. It very much sounds like lug nuts bouncing around in a metal fan.

Any suggestion?

 

My guess would be the chain guides..what have you been using for oil filters?

 

First thing to do is remove the serpentine belt and determine if its just a belt idler pulley, belt tensioner or one of the other FEAD components like A/C, PS. alternator etc. If the noise is gone with belt off then narrow it down to the specific component. Noise still there then start checking for the noise location with a inexspensive stethescope by placing the probe on the front cover, oilpan camcovers, etc. Just keep narrowing it down to a specific location and you will solve it. good luck.

 

Sounds like a bad bearing, tensioner... They sound like marbles in a can sometimes. so follow dynotechs advise and eliminate that by removing the belt.

 

Thanks, I will give that a try.