hrmn - you know what; i didnt check this one: http://www.355nation.net/forum/how-...ervice-bulletin-under-vehicle-heat-shield-rattle-2007-2008-colorado-canyon.html


Anyone with an 04-06 have this one rattle? The bulliten says 07-08

 

i did took it to chevrolet 2nd cat was bad. had to take it there twice for them to realize and ahd to get the service manager to look at it. 2004 3.5

 

i have it in my 04 3.5

 

my exhaust rattles against my lowpro trans crossmember form PDC, but only at very low speeds. Something else you might wanna check

 

same here with the ccc xmember.

 

^x3

 

Another GM defect:

http://www.355nation.net/forum/engine-drivetrain/18154-manifold-heatshield.html

I will make a HOW TO on this because it is a common problem for the 3.5Ls.

 

When I put in my x-member I brought the truck into an exhaust shop and they re-bent the exhaust to clear it. I just went outside and jacked it up again checked every heat shield front-to-back and they are all secure. I also grabbed the entire exhaust and gave it a good shake from a few different places along the pipe and there wasn't anything hitting anywhere.

There is not a change it the way it drives at all so I dont know if its a plugged cat problem.



(from your post in that thread)

I did check that one - however only at the bottom of it while I was under the truck. I didnt check the top side (towards engine bay). I will go back out right now and check.

 

alright. went and checked this shield out. I grabbed onto it with some channel locks and gave it a good shaken from all corners and it didnt seem loose. I gave it a few good whacks with a ball-pean hammer anyways just in case. LOL. I figure it thats the problem that maybe changing the shape will stop it or atleast change how/when it rattles.

any other suggestions though, guys?

 

Yeah one more suggestion: Tear that heat shield off and move on.
It is impossible to check it with out the truck under load... Been there done that, isolated everything else and found it the hard way.

Lay under there and have someone power brake it to 1900 rpms if you want to be risky and technical. :lol:

 

2006 3.5L auto ext cab.

So for the last couple weeks whenever I am accelerating at a moderate rate; I get a rattle / buzz coming from under the cab when I am between 2000 - 2200RPM. I figured for sure that it was the famed heat shield that seems to do this on these trucks. I had it up on the ramps last night and fiddled with the shield above the main cat and although it was "wiggleable" it wasn't coming into contact with anything. I also checked the heat-shield on the manifold as well as the one on the tail pipe, as well as the one at the back of the cab and they are all very secure.

Is there any others that I should be looking at? I didnt check my gas tank but I figure its such a unique range that it was definitely a resonate-frequency vibration.

Would it make sense to get a rattle that unique to such a narrow RPM range if it was the muffler crapping out?





Thanks guys.

I've got it as well, but between 1700-1900 rpm.

 

Just started getting the same kind of sound......'04 3.5 from take off to 10 mph in the 2-3000 RPM range sounds like crap!

 

Have the same thing going on with my 06 3.5. Will try to sort it out this weekend. In the past for heat shields I have used large hose clamps on one at a time and go for a drive with each clamped until you find the offending rattle, then bolt weld, or even leave the hose clamp on.

 

So this morning on the drive in it was still buzzing away - but I think it was worse (which is good) because this indicates that when I smacked this shield it made it buzz more. I will rip it out tonight.

 

It is likely the catalytic convertor in the exhaust manifold. Mine had the exact same buzzing/rattling under load in the same RPM range you describe. Took the upper manifold heat shield off and rattle was still there. Lower mainifold heat shield was tightly welded with no cracks or looseness. Turns out, the catalyst in the manifold was broken and buzzing/rattling around inside the catalytic convertor. Took 3 visits to the dealership for them to finally fix it under warranty.

 

Yeah I have the same issues

 

Well this happened to me.

It was the fuckin O2 sensor, it had come loose and was making all kinds of stupid noise. I tightened that bitch down real good...problem solved.

 

did you figure it out yet?

 

I went all over mine, no loose heat shields or O2 sensor, however the input flange on my flowmaster is cracked over 1é3 of the way around the pipe. Will weld it up tomorrow morning an hope.

 

been raining all day - hopefully can tackle this tomorrow.

 

Did you figure it out yet?

 

This just started happening to me a fews days ago. When I start out in 1st at roughly 2K I hear a slight "rattle", then again right after shifting into 2nd. I shift fine, the clutch feels good and driving ok. Reading about these failing heatshields I'm 99% that's what it is...thank goodness to! I can't afford an f'n repair bill right now!

 

OK this is weird. My rattling STOPPED this morning. Im not gonna bother ripping it off unless it starts up again.

 

My rattle was caused by cracks around the input flange on my Flowmaster, upon further examination the larger end piece was also cracked about half way around. Welded it up last nite and the rattle is all gone. Definitely not a testament to Flowmaster. However I will give them and opportunity to make it right as it is still under their 3 year warranty.
Funny I have run the old turbo mufflers at 20.00 a pop on my old rock crawling jeep, beat them and dented them and never had a crack.......

 

i got the best bet for those lower heat shield rattles... if you dont want to take it off... get 2 hose clamps.. i think they were 4 or 5 " ones for like a dryer vent, pop them on the top and bottom and crank them down... fixed mine right up.. i have a glasspack on my truck and my 2100rpm rattle was louder than the pipe!

 

i put a big hose clamp around that heat shield on the 1st cat the noise is gone

 

Well mine continued cracking after stop drilling the crack and welding. Flowmaster replaced it under warranty. Welded it back in last weekend. No noise now.