Our company has a '10 Grand Caravan SE with the 3.3 V6 engine and at cooler temperatures, below 45 degrees(F) mainly, we experience some slight exhaust resonating when first starting out and prior to the engine being up to full operating temperature.

I have noticed it on occasion now during the summer months, but it is so random it would be hard to duplicate it for the service techs. May need to wait until winter.

Had our selling dealer look at it but were unable to find anything wrong.

I'm thinking it possibly could be an internal problem within the exhaust components.


Anyone else notice this with their vans?

 

I have the same exact sound like humming noise and a little vibration coming from engine compartment or slightly underneath the front seats. It only appears when starting on cold for a couple of minutes until the engine heats up a little.
As far as I understand it's the Catalytic Converter (CAT) located right behind the engine in the center of the car underneath. I think it's the plates in the CAT warming up that make that noise when exhaust gases flow through it. However, I may be wrong. Tried to search for a CAT to replace it(though other than the noise CAT works perfectly), but they are expensive - around $300-400. I guess it's just the engineering flaw in the design of the exhaust system.

 

Almost like a throaty sound? I have it too. Just needs to be a bit louder

 

There is a TSB in the works for the cold engine exhaust drone. It should be out in the next few weeks. I'll try and keep you posted when it is available (I have a bad memory )

 

In any case, if it comes down to it, the cat converter is covered for up to 8 years or 80K miles under a federal emissions warranty.

 

Thanks Tizzy1 - that sound is a mystery to me. I would really want to know what is causing it.

 

Thanks Cougar41! It's good to know that CAT is covered. However, I don't know if that sound can be enough to replace CAT under warranty - because besides the sound the CAT works just fine. It has good emission numbers and so on. It's just really annoying sound when I start up the vehicle on the morning and it starts to vibrate and hum.

 

There is a tech tip that say's replacing the exhaust or cat will not eliminate the noise. They are coming out with a weight package that we will attach to the exhaust to absorb the vibration.

 

Wow, that's interesting. Would I be able to buy it from dealer (I am probably not on the warranty anymore)? Tizzy1 thanks for the info! Please keep us updated on this

 

I would assume you could purchase the parts package when it comes out. I'll keep an eye on it.