The heat shield on my daughter's 2008 Chevy Cobalt has fell loose and is supported only because it sits on top of the exhaust. There are what appears to be pins that it clipped to...I can still push it up in place and it attaches to the pins on one side (but not the other), but it pops free almost immediatly after I do so. How can it best be re-attached?

Sounds like you have a loose heat shield that is a piece of tin between your exhaust pipe and floor of vehicle. These can rattle pretty bad. While the noise is there, look under vehicle and you may see where it's loose, or corroded.. If you get under the vehicle when it is cooled off, you can probably locat this loose shield within seconds. If it is not loose, wiggle your exhaust pipe and E brake cable. Hopefully you will find something loose

Hi,
Likely an exhaust heat shield. When the SUV is cold - after sitting for 4+ hours - crawl under the vehicle and see if any of the shields are loose that cover the exhaust pipes. If they are you can use sheet metal screws screwed into the shield and against the exhaust pipeto 'wedge' the shield so it doesn't move.

GL,
Td

Hello Lisa,
Rattles are always a fun thing to chase after. The first thing that comes to mind with a rattle under acceleration would be a heat sheild. Over time, heat shields which protect the under body of the car from exhaust heat come loose. Might want to have an exhaust shop take a look at it for you. I have heard of weak tack welds located on the heat sheilds by the catalytic converter. So you can ask an exhaust shop to take a look.

Although if you are one to get down under the car and a bit dirty check it out on your own. You might be able to check without putting the truck on a jack stands or a lift. Basically you will want to ensure the car is cold. If the car has not sit for a little while, I would not recommend touching the exhaust. YOU WILL get burned. :) Once your sure its cold and want to squeeze under the truck you can follow the exhaust tips all the way up to the catalytic converters. See pic below(number 16 is the heat shield). You will see the tin around them and be able to shake them a bit. If you hear your rattle there is your problem. If not check out the other heat shields.



Good luck

A common cause for the "rattling" noise you've described is a loose heat shield for the catalytic converter. Many times, a weld will break loose leaving you with a hanging heat shield that vibrates and "rattles" while you drive. A trip to the muffler shop should be able to confirm this. By itself, a loose heat shield is not something major.

Another cause could be a loose exhaust hanger that holds the exhaust firmly in place. It too would tend to rattle more as you drive. Either way, it would appear on the surface that your issue is exhaust related. Best of luck and thank you for using Fixya!
Greg

Well it sounds like either the muffler itself has a rupture in the outer shell or the exhaust pipe going into the inlet may have a hole or a bad weld (or loose clamp if it's not welded in place) as to the heat shield you'ld just need to raise & support the vehicle and really inspect exhaust to pinpoint problem and see if the heat shield has been replaced too. I'd imagine the top of the muffler has blown out and all that heat is hitting the trunk pan and melting your carpet

Hi, place the Cobalt in "Park" on a level surface. Allow the Chevy to sit for 10 minutes. This will allow components to cool enough to touch but still be warm, which is ideal for replacing the oxygen sensor. Open the hood of the Cobalt and identify the oxygen sensor. Look for a white, rubber, plug-type sensor on the passenger side of the exhaust manifold; this is the oxygen sensor. Use a socket wrench paired with an oxygen sensor socket to loosen the sensor. Turn the wrench counter-clockwise until the oxygen sensor is loose. Remove the sensor from the manifold by pulling it off. The sensor will come off without much force. Insert the replacement oxygen sensor onto the manifold. Secure the sensor by pushing it into place until the sensor clicks. Close the hood of the Cobalt.
Take care

Most likely the heat shield has corroded off and is just sitting on top of the muffler or Catalytic converter. Regardless you can remove the shield and still run the the Xterra without any problems, the OEM muffler came with a heat shield as to the after market mufflers don't have one. The Catalytic converter also has a shield and you can remove it also as the Xterra has a heat shield on the floor board it self. Most exhaust shop if honest will tell you to just remove the rattling shield if there is no exhaust leaks or no Check engine light on that monitor's the Catalytic converter's performance.
A muffler shop if shady may advise you to replace the Catalytic converter and that can go for up to and beyond $400.00, so as long as there is no leaks or check engine light on. Go right ahead and remove the rattling shield.
Thank you for using Fixya

the cobalts have a very thin walled exhaust and also have a heat shield wraped muffler, the clicking noise you are refering to im guessing is more of a "tink" noise? if it is, its the exhaust cooling down and contracting

Hi there
Just take it into the exhaust people and tell them that you need a new muffler ONLY. welded into the place of old one as all your problem is the BAFFEL plates have come loose and the welding is only spot welded and isent any good So a new muffler is ALL YOU WANT
Ron

It’s your solenoid that is getting hot and the engagement washer inside is what is sticking. There is some heat shield material you can get from the auto parts store to shield you solenoid.