Blown cat?

[destroyer1362]

Last weekend I drive about 450-500 miles to Houston and back. When I got home my exhaust sounded different.. Louder, with a little bit of a pop or a rattle. I thought it may had been a sticky lifter but I can't hear the funny sound under the hood at all. Its been seafoamed, runs Mobile1 synthetic w/ lucas. I noticed my exhaust sounding louder about 75 miles before I got back. btw all the way down and all the way back I averaged about 75mph to 90mph. After I noticed the sound change there was no difference in mileage or power to me. And as of now its not throwing any codes or ses light. I don't know what it could be. I will be trying to rule it out as an exhaust leak later tonight. Unless its the cat I have no idea what it could be. Any ideas?

 

[bai78]

I had a bit of ticking as of late. When I checked underneath the collectors were loose. After I torqued everything down with some loctite, the noise was gone.

 

[ravingmadman]

You can put your hand over the end of the tail pipe, and see if it's developing pressure. If you have a leak, you'll be able to keep your hand on the pipe, and it will hiss where it's blown through. Even if it's a pin hole.

You'll need a friend (I asked my wife, and she was NOT happy after; I recommend beer drinking man buddy) to help you locate the leak if that's the case. Otherwise, unless it's throwing obvious codes, don't worry about it. If you have a real problem, you'll get a code, and you'll fail emissions.

Watch your MPG, too. Obstruction of exhaust gasses will kill your MPG, torque, and HP- but your MPG will go first, so you'll know something's up.

 

[bowtiefreak]

Typically when mine has blown cats it rattles, smacking the cat will stop or increase the rattle inside. Pretty common on our trucks to blow the cats, I went through three I think and upgraded to a magnaflow and have no had a problem yet.

 

[destroyer1362]

So I tightened everything down. 3 out of my 4 band clamps were loose. I got all of them tightened except for the one after the muffler. I covered the end of the tail pipe and I got a hissing coming from the same spot as well. The exhaust is quieter now but I still have the tick/rattle sound coming after the muffler and the out the tailpipe. Will that little leak after the muffler cause that noise I'm hearing? I'm throwing a turn down on it for now if I can't stop the leak.