Rattle on start-up

when i crank my X up after it has been sitting for a while it makes a horrible rattling noise for several seconds. lately it has started to do it momentarily while driving also. i also had a slight belt squeek. so today i checked it out, i ended up replacing 2 of the belts just to be on the safe side and the squeek stopped. the rattle didnt. i think it is one of the pulleys, but i cant tell which one. it seems to be in the middle to drivers side area, just cant pinpoint it. anyone else had this super annoying rattle on cold start-ups? any advice, i dont know what to replace...

It's common to get a steady tap-tap-tap-tap at startup for a few seconds (lifter noise due to oil starvation) - but that doesn't really sound like what you're describing...

After replacing the belts did you tighten the locking nuts/bolts?

Not valve noise... it is definitely belt or pulley, or fan related. its really pissin me off, i could fix it in 5 mins if i knew what the hell it was. yes the belts are tightened correctly. the more i listen for it, it almost seems to be coming from the crank pulley but not sure. closest thing i can think of to describe it sounds like a bolt rattling around in a can. not necessarily even a regular pattern, sorta random, like something bouncing around. its the weirdest thing ive ever heard.

could it be the manifold heat shield? If a bolt was loose or broken, it will vibrate at certain RPM

You may want to double check the belt routing and the tensioner...my .02

i cant figure this out, its pissin me off. im really starting to think that its the crank pulley thats making the racket. is that even possible, anyone ever heard of a crank pulley making an obnoxious rattling sound?

Its not that farting sound as soon as you turn the key to the on position is it?

nope, 1-2 seconds after cranking it makes the noise for about 10-15 seconds when the engine is cold. it stops if you put the truck in gear and take off. however, if you stop (in gear) again while its still cold, it will continue to make the noise intermittently. put it in park or press the gas a little (foot on or off the brake) and it quits. once the truck is warmed up, you can turn it off and crank it up and its fine.

I had the exact same symptoms - and was going crazy in the engine bay trying to figure out where the noise was coming from.

My problem was a loose section on the exhaust - It wasn't the heat sheild but rather part of a clamp around a enlarged part of the exhaust under the drivers seat.

The loose part would rattle until the exhaust got warm and expanded enough to prevent the loose part from moving.

Water pump? When they start to go bad, it sounds like some marbles rolling around inside the engine.

How many miles on the truck?

87k on the truck, runs and drives perfect. the noise really sounds external, definitely from the front and low area of the engine bay. going to get under there AGAIN today while someone cranks it for me....

Mine does it too, and the noise seems to be coming from the front of the engine around the distributor. It stops shortly after startup when the engine starts to warm.

Mine's been doing the same for the past couple of months. Seems to be worse when it is cold outside. When I left work this evening (about 40F outside), I decided to pop the hood and listen a little closer. Mine sounds like the top of the engine near the distributor, too. Mine will turn over 98k miles tomorrow.

I've been in Germany for the past six months and just got home. I was very excited to finally drive my X that my sister-in-law has been driving and notice the obnoxious noise you are describing. I have tracked it down to the alternator pulley on the crankshaft. The other two pulleys on the crank are tight but not the third.

And now for my problem...my X manual is on my desktop computer in Germany, but I need to do some work on it now. Anybody have a page or two of the manual they could email me to show how the crank comes apart?

This really sucks. I thought I could go wheeling while I was back, but am instead fixing my truck...

If it's not to complicated I'll do myself, although my X still has the powertrain warranty so I could get the dealer to do it.