Oldchevy4x4

Well it's time to throw in the towel and get some help on this one. Ok my wife has a 07 SS with the 2.4 and auto with 90k. A little while back she noticed the occasional noise (like a rattle, but sounded like the timing chain) during sudden acceleration around the 2000-3500rpm range. Then about 2 weeks ago it got worse to being almost all the time it was above 2500. So I read up on it and went ahead and replaced the timing chain, guides, and tensioner with the Cloyes set from SummitRacing. While I was in there I also replaced the water pump and the tensioner for the balance shaft/water pump chain because that one felt like crap trying to crompress it to put in a paper clip.

Yesterday I got it all rapped up and going again. Started it up and no noise!! Then when I drove it out of the shop and punched it a little I notice the original noise is still there now. It sounds like a chain rubbing but it is fairly faint. It only does it when you stomp it a little and only in gear. Any ideas? I'm plum out and my wife really wants her car back!

jdbaugh1

iTrader: (1)

Is it possible that it could be your exhaust vibrating against something or has something loose and is rattling or is it for sure coming from the front side of the engine?

Slowbalt2000

iTrader: (1)

Try revving in neutral and listening with the hood up to see if you cant pinpoint it.

Oldchevy4x4

It could be something rattling. I am haven't had much time to try and find where the sound is coming from yet. The problem is it only does it when moving. If it's in neutral or park it sounds perfectly fine. So that should eliminate the chains because they should only be affected by rpm and not engine load. Unfortunately I had to spend today working on my truck because my jeep is down. I work 2nd so Hopefully tomorrow I can try and figure it out.

Oldchevy4x4

Ok after futsing with it this morning I'm about 95% convinced it's an exhaust leak. It goes perfectly with engine load and rpm. But if you have the rpms up and let off the gas it goes away. Right now it's cooling off so I can try to find it. I feel really stupid at the moment!

Since im here is there anywhere these are known for leaking up around the manifold?

jdbaugh1

iTrader: (1)

Don't worry about it. Definitely didn't hurt anything by replacing the timing chain. Only place I know of is the upper flex section on the downpipe tends to crack from fatigue over time. It could definitely make a rattle noise too. Mine made terrible noises but it just got worse and worse until I replaced it.

Slowbalt2000

iTrader: (1)

Ive seen the cast manifolds crack right down the center, but also the flex pipe is a common failure

Oldchevy4x4

Well when my wife got home I had her power brake it so I could listen in the engine bay. I could hear a chain noise from the engine but it was way deeper and I'm pretty sure just normal. I can't manage to make out the noise from the engine bay. Only from inside the car where it is really obvious. I tried with my head down by the ground and couldn't hear anything from down there ether...

I told her to drive it and I'll check it out when it gets worse and if it blows then I'll know what it is lol. But she is being really stubborn on this one with worrying about it just blowing up and leaving her stranded.

Slowbalt2000

iTrader: (1)

Was the chain tensioner extended when you installed it, or did you put it in compressed and then "set" it?

Slowbalt2000

iTrader: (1)

A lot of times the upper guide bolt will break off in the head too, but if you just replaced it i doubt thats the issue.

Oldchevy4x4

I'm pretty sure the bolts should all be fine. As for the tensioner I installed it compressed and then tried to activate it but couldn't get it to. So I read up on it some more and found numerous people saying the new style are hydraulic and don't need activated anymore. Is that true? I pretty much ruled that out though do to the fact that the noise is very dependent on engine load.

jdbaugh1

iTrader: (1)

Think you would be able to take a decent video that would demonstrate the issue you are having?

WICobaltSS

The Cloyes chain tensioner I installed was sent in the compressed state. Thought something was wrong with it until I googled the directions and it said to take a long screwdriver and carefully pry against the tensioner until it "pops" If that's the case, you'd just have to pull the valve cover to do it.
Slowbalt, funny you should mention the upper chain guide bolt breaking. Working on my Daughter's Ion right now and the guide bolt is busted. Still figuring how to get that out...

Oldchevy4x4

Best I can manage. You can hear it but it's very faint. It sounds like it comes from right behind the glove box (front the engine).


Ok apparently it didn't attach. I'll try it again again later

clintsal

I've got the same problem on my 2.4, going to start w timing chain same as you, curious to see if you find an exhaust-related culprit