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Discussion Starter #1
Recently there's been a strange noise coming from the exhaust, the sound isn't there when driving but shows up at low idle. It sounds like "bub, bub, bub, bub..." but only on low idle. I don't feel any loss of power and the scangauge isn't showing any codes or overtemp. It seems to be a little worse in the cold weather. Any ideas? Stock engine & exhaust but does have a CAI. I first noticed this in the fall but seems to be happening more often. I'd like some ideas before I run to the dealer, wrong time of year for major car repairs, maybe covered by extended warranty?
 

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..take a good look at the gasket in the flex pipe to cat union...as cold weather sits in metal shrinks and may allow the gasket to blow out...

Jetfuel...next...
 

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Discussion Starter #4
Jetfuel, this started before the cold set in, but I'll see if I can check the gasket tomorrow.
Gasket or cracked flex pipe I think the warranty will cover them.
 

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..cool...also since you mentioned the CAI check it to make sure it is not hitting anything...this engines do move quite a bit at idle...I think one of our young members had an issue like that a while back....

Jetfuel...good luck...
 

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Are you certain it's coming from the exhaust?

The purge valve, particularly on earlier cars, can often make a sort of popping/sewing machine noise when the car is idling. Individuals have done various things in an attempt to silence it, from installing dampening material around it to completely replacing it, but the noise itself it not cause for concern if it is indeed originating from the purge valve.
 

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Discussion Starter #8
Not purge valve, this happens any time of the day when at low idle only, I know the sound the purge valve makes and this isn't it.
 

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While the engine is idling and making the sound have a helper hold a folded rag over the end of the tail pipe. If the exhaust is leaking you should be able to hear its location. It may help to wiggle the tail pipe up and down. Also, you get to laugh at your helper when they hold the rag on too long and it gets real hot and they start cursing at you.
 

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Discussion Starter #11
Extended warranty to the rescue! Car's in the dealership & I've got a rental (a Hyundai) (sp?) I'll find out tomorrow what's wrong. Since I'm paying for the warranty I just as well use it.
 

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...let us know the outcome please...
...is it an Elantra??

Jetfuel...drive it like a rented mule.......it's a loaner....
 

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I'm not a stranger to rear end noises. Most of the time the best choice of action is to try to ignore them. I know it's the expedient thing to do but in the end, things do usually work themselves out. (tried to put a smilie in here but software refused to cooperate)

It will be interesting to find our how things worked out for you.
 

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...rear end noises are famous at the Dragon run right after the Mexican dinner..

Jetfuel...you know who you are .....right Barney????
 

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If you find that half dollar under the seat of the rental...its mine. I couldn't get it out! :) Let us know what the diagnosis is.
 

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Discussion Starter #18
...let us know the outcome please...
...is it an Elantra??

Jetfuel...drive it like a rented mule.......it's a loaner....
Nope, Sonata. I drove it like it was mine. It turns out the warranty didn't help, I was rear-ended a month ago, no visible damage other than the panel over the bumper, which was replaced. My trailer hitch was knocked back to where it just barely touching the muffler. With high revs the engine was smooth but with low idle it was a little rough, rough enough to knock against the hitch. The techs at the dealership loosened the bolts and shifted the hitch back and retightened the bolts. No noise now. Wish I had access to a lift, would have saved some $.
 

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I've tried that but someone usually smells it and rats me out. :D
Yes, but you see, if you're forward looking it should all be beneath or behind you. Just keep a steady grip, a stiff upper lip, and a steely forward gaze and all will be well.
If you smell a rat, just move on.
 
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