its very loud at idle but very quite on highway please help do I need a engine

 

Well to start things off we need to know a little more about your truck. Year? Stick? Automatic?

 

It's most likely your number 8 injector.

Hammer

 

My 00 does the same thing i used to worry about it but after my oil came out looking fine ever time i figured it was ok. It still makes me wonder though. Does your knock seem like it does it when it want s to ,almost not insink with the rest of the motor and just a few times a min.

 

Mine does the exact same thing. On my truck, it comes and goes, only notice it at idle. had the dealer inspect twice. They said get used to it. #8 injector. I have run additives to the fuel but it does not help. good luck!!

 

This truck is 99 powerstroke diesal 7.3 the knock is out of sink with the engine the truck only has 40k on it. its like something is loose but only happens at idle when it knocks it sounds like its not in sink with engine at all. its a random knock only at idle.

 

I took the truck to a ford dealer and they changed the torqe converter to no avail. then they said it must be in the moter. this truck is a 99 automatic 7.3 diesal. Thats a good Idea to change the oil. but this knock is loud! again only at idle. The dealer wants 10k for rebuilt motor! I dont know what to do!

 

Two things come to mind: The most likely suspect is a bad injector. It also could be a worn out valve guide. You're going to need someone who knows to look at the engine.

 

its a 99 automatic f 450 its very loud at idle but quite as a mouse on the highway! I noticed more that when I put in gear it goes away most of the time. thanks Bob!

 

Wow all these posts appeared while I was typing. Those torque converters are notorious for making noise. Some people add a switch to manually lock the converters and shut them up while the truck is in park or neutral.

 

I know on our (international) side there is an knock issue @ idle w/ split shot injectors. Ill look tommorrow but i think its a programming issue or a problem w/ #8 injector.

 

Along with what International Tech was saying Ford issued a TSB about 3 years ago regarding "cackle" noise or engine knock above the normal sound of Diesel engine combustion. May sound like a rod knock although intermittent and increases in intensity as the engine warms up to operating temperature. Noise may originate in the fuel rail and almost always attributed to #8 cylinder. The fix was either replace #8 injector or PCM reprogramming. I had the above symptoms and got it fixed under warranty. Ford reprogramed PCM and noise went away - dealer said if that didn't fix it to bring it back and they would replace #8 injector.

 

Thanks for all your help I am going to the ford dealer armed with this great data! Bob!

 

I have a knock and a rattle at idle only too. I have a '97 F350 with a 5 speed. I have been told it is the dual mass flywheel going out. I saw on this site a few weeks ago, an article on how to replace it. Does anyone know were I saw it? Also, could this rattle and knock be caused by something else?

 

thanks for all the info guys i was always kinda worried about it but glad im not the only one.