I have been getting a rattling/metal clanging noise (excuse the weak description) when I am accelerating over 45mph. when I let off the gas, the noise stops. This started last week as very intermitent and now is very regular
I currently need new u-joints but I am not sure if this is associated with it. No vibration either, just a rattling/clanging noise..any ideas?

 

What motor ? How many miles ?

 

would you happen to know whether its coming from the engine? exhaust? under truck? does it only occur in a certain gear? if so which one? heavy or light acceleration? is there any noticeable difference in performance?

 

no change in performance, just strange noise. 5.4l v8 2004 F150 4x4. I can't tell where it is coming from since it only happens above 45mph. so every time I stick my head out the window and try and listen..so frustrating.

I did just get a new muffler put on and they told me that they tightened up the bolts from the down pipe to the manifolds because they were loose..

Does not sound like exhaust leak but does sound lik eit is coming from the engine..definetely a rattling noise. WTF???

 

I'll try again = How many miles?

I think Matt knows what it is too lol.

 

i dought its your exhaust shields if its at higher speeds, but you could still check them. what kind of gas do you use? what kind of oil and filter do you use? and is it under heavy acceleration or light acceleration? high or low rpm? or does it not matter? may not be getting enough oil pressure to the timing chain tensioners.

 

Yea , the older pre-04's would do that at or just above idle. I just had a Crown Vic fixed under the Emissions warrenty (that's why I keep asking for miles) for someone else that did the same exact thing the OP descibes, -it's still in my driveway - A 2004 cat heat shield - They replaced the Cat under the Emissions warrenty.

 

they replaced the whole cat for a heat shield? dang, ford must be desperate to keep their customers or something. first they warranty an engine with 65k miles without an oil change, and now a cv cat replaced for a simple heat shield.

 

mileage is 45,000 and this noise is intermitten..sometimes it does it sometimes not. Not heavy accellerating, just regualr driving. As soon as I get near 50mph it will make the noise until I let of the gas then it goes away for a few minutes..Truck is overdue by 2000 miles for an oil change however there is plenty of oil, and all other fluids appear good. I use regular gas.

 

what kind of oil? how often do you normally change it? it may have sludged up the tensioners but beat on the exhaust system to make sure its not the heat shields. what kind of gas do you use?

 

Sounds like pinging/detonation to me.

Could be from a bad tank of gas, or not enough octane. Easy to rule out by switching fuel suppliers and putting a tank of premium in at next fill up. If the sound goes away, it was pinging. If the sound remains, explore other problems.

Can also be caused if your cooling system is not working properly and the motor is running hot.

 

Yea, the cat shields are just spot welded from Ford. It's probably more cost effective to replace rather than weld up. I know you can't weld them in place lol.

The sound,- under normal driving conditions comes and goes. Sounds like a fast metal clapping sound or vibration. Kinduh like a kazoo lol.

Emissions warranty is either 80,000 or 100,000 miles, -that's for everyone.

RI04F150 -Take it in , tell them it sounds like the converters are falling apart. -If you think that's what it is.

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Yea, did you read that lol. I can't believe it!! Someone must have had a gun to their head.

 

Too bad I have a full custom exhaust from the headers down..no warranty for me..As for the oil 5w-40 and like I said its overdue so maybe thats it.

No heat shield, already ripped both off in the past and I banged all over the exhaust with no rattling..so ruling that out.

Totally baffled, and this started right after my serp belt was replaced and the muffler was replaced..bringing it in tommorrow to the last guy who worked on it. PIA!

Thanks for all the attempts at diagnosing this, nice to be able to bounce these things off other people before getting "raked over the coals" at the mech shop..

 

jbrew- that description of the sound is pretty accurate to what I am hearing..its almost like a chain shaking or something like that..

 

Your engine requires 5w-20. The oil could be the source of the problem 3v engine cam phasers.. Motor craft filters and the recommended/required 5-20 are absolutely critical in those engines.