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View Full Version : Car question: Does this sound like a resonator problem?


crazyjoe
02-25-2010, 12:32 PM
When starting my car from cold, it is pretty loud...not just high-rpm loud, but exhaust-noise loud. It's loud while idling and loud while driving around.

Once it warms up, the sound becomes much less noticeable.

A local shop wants 500 to replace my exhaust system because they say I have a bad resonator. While I am pretty confident that replacing my whole exhaust system will fix the problem, I am not sure it's a resonator that's really the root cause, and since I am probably going to attempt a holdover patch until I get five hundred bucks, I am interested in other possibilities.

Gbro
02-25-2010, 12:37 PM
Resonator's make some awful sounds when bad. I will be interested in the outcome of your issue.

SmellMyWort
02-25-2010, 01:00 PM
How old (and rusty) is your car and have you tried to identify the source of the noise? Exhaust systems come in parts and you might be able to get away with just replacing one section. Bet you can find it online for cheaper than the shop wants too, and if it's not too rusty under there you might be able to swap it out yourself.

Philster
02-25-2010, 01:06 PM
If the whole thing is going, you'd want to replace all of it. Sometimes the joints and resonators go first, making a racket. But when you inspect it, it's obvious the whole thing is going. Sure, one spot is making the most noise, but the whole thing is turning to crap.

Car?
Year?
Model?
Mileage?
Area used?
Etc.

crazyjoe
02-25-2010, 01:19 PM
2004 Dodge Stratus SXT, V6, 2.7L
76K miles.
Used in Michigan. Combination highway and city driving.

simple homer
02-25-2010, 01:29 PM
My guess is that the resonator, if it has one, is further back on the exhaust system and would not be that loud.
Sounds like an exhaust manifold leak to me. As it heats up it expands and seals the leak

I would recommend getting a second opinion.

Gary T
02-25-2010, 01:29 PM
Once it warms up, the sound becomes much less noticeable.This is not impossible for a resonator, but it's not usual either. It's more common for a cracked exhaust manifold. If it is a manifold problem, the noise would be coming from the front (engine area) rather than from under the passenger compartment. Nevertheless, I would suggest a second opinion to verify or rule out the resonator.

simple homer
02-25-2010, 01:36 PM
This is not impossible for a resonator, but it's not usual either. It's more common for a cracked exhaust manifold. If it is a manifold problem, the noise would be coming from the front (engine area) rather than from under the passenger compartment. Nevertheless, I would suggest a second opinion to verify or rule out the resonator.


I am very honored that my answer would be almost the same as the resident car expert.
Thanks ! :)

crazyjoe
02-25-2010, 02:41 PM
This is not impossible for a resonator, but it's not usual either. It's more common for a cracked exhaust manifold. If it is a manifold problem, the noise would be coming from the front (engine area) rather than from under the passenger compartment. Nevertheless, I would suggest a second opinion to verify or rule out the resonator.

I thought so, too. The noise does come from the front area of the car (though due to it's cab forward design, it also present itself from beneath the driver's feet).

Thank you all for confirming my suspicions. Perhaps my mechanics are not as good as I thought they are.

SanDiegoTim
02-25-2010, 03:39 PM
With the noise level higher on start-up and lower with warm-up, it sounds like (at least partially) a bad gasket somewhere. I say this because, while not common, something is expanding with inceased heat. If a gasket, the seal is better when warm. If eminating from the engine/front area, could be the gasket between the cylinder head and exhaust manifold or between the exhaust manifold and header pipe.

I'd certainly try to narrow down the source before biting on a new exhaust system. BTW, eliminating the resonator, depending on the vehicle and your tolerance for decibel level, sometimes isn't a big deal.

smithpc44
05-12-2016, 11:11 AM
I have a 2005 Nissan Xterra. I am having some type of issue with the exhaust. Let me first say that I am NOT a mechanic so I will do the best I can to describe what is going on. I am hearing a loud vibration when I accelerate. It seems to be coming from underneath the drivers side seat. It really only happens when I am switching between 1st and 2nd gear. I crawled underneath to try and wedge something (wood, rag) under the metal flashing that covers the exhaust. It seems to help a little but definitely got worse after I removed it. I took my car in for an oil change and the technician said I had a bad resonator. I honestly have no idea what that means. Any help for ideas on what this might be would be greatly appreciated.

Tired and Cranky
05-12-2016, 12:01 PM
I have a 2005 Nissan Xterra. I am having some type of issue with the exhaust. Let me first say that I am NOT a mechanic so I will do the best I can to describe what is going on. I am hearing a loud vibration when I accelerate. It seems to be coming from underneath the drivers side seat. It really only happens when I am switching between 1st and 2nd gear. I crawled underneath to try and wedge something (wood, rag) under the metal flashing that covers the exhaust. It seems to help a little but definitely got worse after I removed it. I took my car in for an oil change and the technician said I had a bad resonator. I honestly have no idea what that means. Any help for ideas on what this might be would be greatly appreciated.

Did your mechanic explain why he thought it was the resonator? How did he check it? Did he look at it and spot the problem, or did you just describe the symptoms to him and that's what he thought it might be?

You say you hear a vibration. A vibration is something you feel, not something you hear. I'm not trying to be a jerk, I'm trying to understand the noise better. Does it sound like rattling metal or like a really loud exhaust noise? Those might be very different issues.

The "metal flashing that covers the exhaust" sounds like you might be talking about the heat shield over the catalytic converter. These often get rusty and damaged by road debris, then they rattle. If this is the noise you are hearing, they are cheap to replace. Probably cheaper than a resonator. You shouldn't stick cloth up there to silence the noise because it could catch fire. The catalytic converter has a surface temperature of hundreds of degrees when the car warms up.

Doctor Jackson
05-12-2016, 03:37 PM
I crawled underneath to try and wedge something (wood, rag) under the metal flashing that covers the exhaust. It seems to help a little but definitely got worse after I removed it.

And it has to be said - putting anything combustible on or near the exhaust system of a car is highly contraindicated!

jz78817
05-12-2016, 06:36 PM
a "resonator" is basically a hollow chamber which is in there to help cancel out a "drone" at a particular frequency. the only way one would go bad is if it rusted through, and at that point it's just a garden variety exhaust leak.