Any input on what could cause a rattling sound when I startup a cold engine and then when at idle when I step the gas to rev it up?
It sounds like a loose ring shaking and I looked inside with the engine running and all seems fine! Arghh... I just had my muffler fixed and am low on funds! mannnn... what could this be now?

 

maybe you forgot your phone inside the engine bay....

could it be a knock sound... a valve maybe?!!!!

 

Did a hose clamp loosten and vibrate against the block?

 

haha... I wish it was that...
It sounds more like a big loose washer just rattling somewhere!
It's pretty loud and I can hear it inside!

 

hmm.... I dont know anything about the engine, so I wouldnt know how to begin with this... I am afraid to go to the Stealership, but I dont want to make it worse!

 

Can you make a short video clip of the sound for us ? Make sure it has AUDIO - duhhh. If the noise is there when you rev up the engine.... check your oil level, it is a 3.5L so ya should check it periodically.

 

I think i know what your talking about, i have the 3 liter but mine happens when im driving, like taking off from a stop light or shifting 2nd to 3rd, its like a loud metal ring, like u left screws or something in the engine bay on a metal case and they were shaking really fast. kinda hard to describe but i know what ya mean

 

That sounds like a loose heat shield...

I took all of mine off before I put on my headers because one of them got loose.

 

Let me see if i can get an audio clip of it...

 

I just got the oil changed by the stealership...
I forgot to mention the sound while I was there, cuz the sounds was soo low at first.. but its getting worse!

 

How bad is it to get it fixed?
Where do I look for this?

 

oh.. btw.. I always put Premium, Could the Ethanol in fuel trigger any of this?

 

Crawl under car with socket set, locate heatshields and remove them.

The heatshields are just thin metal covers over certain parts of the exhaust.

 

I think I know what you mean now!
I will look at them tomorrow!!!

 

they get loose eh? probly the cause of it then, its amazing the simple crap that goes wrong that sounds so easy to fix and would cost hundreds at the stealer if you went right ot them

 

guys... I was having someone looking at this issue, but sure enough It didnt make any sound when I was there until I left the place! arghhh!

 

I would say that it's probably a heat shield that has come loose.

 

I did check out the bottom of the car while it was on the lift and didnt notice anything loose... I tried pushing things around and didnt notice anything out of the ordinary...

 

I have the same noise, like you left a bolt or something behind in the engine, it got so bad once the engine did not want to run keep idle crazy, then out of now were the nosie went away idle went to normal and car drives like new, im thinking it has something to do with the valve timeing. Its like the ecu is opening the valves out of sinc with rest of the engine. Its scary i tell you, like your about to drop a rod.

P.S. are the 3.5s interference engines? (meaning will a piston hit a valve if it remains open)

 

it might be your bpipe hitting against your heat shield by the gas tank, cause i know that right now my greddy bpipe is hitting against my heat shield and making that metal noise

 

yes, but your timing chain is pretty durable and shouldn't need to be replaced so you don't have to worry about it. If you had the rattle, it was probably your oil level. Check it at 1,000 miles, 2,000 miles and 3,000 miles after your next oil change. If you're consuming more than 1 qt/1,000 miles and you are still under warranty, take it to the dealership ASAP. you might get a new engine out of it.

Trust me, if anyone knows oil consumption on here, it's me....

 

my car did the same thing, it sounds like a fan touching a little piece of metal, its becoz the pistonz or headers are dirty. make sure you fuel up with premium fuel ethanol to do a little clean up.

 

no ethanol i meant tactrol sorry :P

 

I don't think I've seen Tactrol being sold in the US. I don't think Canadians want to share that little "detergent" additive (Petro-Canada). It seems it's just like any other fuel additive being sold, just a different name.

As for the 3.5s being tagged as oil burners, I've never had this problem (burning, rattling, or otherwise...at least I hope I won't have these problems).

 

BuMp
So, I went in today for an oil change at the dealer and had them look at the ringing sound... They confirmed it wasnt the heatshield..
Now, they wanted me to make an appt to go in and get the Cat replaced...
Its covered under the factory warranty... so hope all goes well and I will post back...

 

common problem on the 3.5s. cold startup, theres a rattling for the first second or two. when accelerating, theres a rattle around 1800-2000 rpms. search a few pages back, theres a thread but i dont think anyone figured it out yet. once in a while i get that problem too but i got used to it so it doesnt really bother me anymore

 

It seems like ever car Ive owned had an heating shield issue. As soon as I relocated to florida from boston my heat shield starts rattling. Very annoying but not a major problem. I also just take em off

 

Alright... here's the latest on this issue...
Brought it into the Dealership and they replaced the Main Cat as it had loose components inside... It was covered under the Emissions Warranty... phew..