2013 Accord V6 engine noise

My 2013 Accord V6 EX-L with 5,000 miles emits a strange sound, under certain circumstances. The sound is hard to describe but reminds me of the old days when your engine would “ping” or “knock” if you used gas with too little octane. Of course, the current Accord only requires regular gas. At any rate when cruising between about 45 and 60 MPH, if you push on the accelerator (not enough to cause a downshift) and especially if on a small incline, you hear a very distinct knocking or rattling sound. Over the past 6 months, the sound seems to become more frequent and noticeable.

I have been to the dealer and the service manager drove the car and agrees he hears the sound. But after consulting with Honda engineering they concluded it is “characteristic” of this engine. They say it emanates from the “paddles” (??) within the automatic transmission vibrating or rattling. After being told that, I drove 2 other 2013 V6 Accords on their lot, and they both made the same sound. My question is, do any other owners notice this? I find it very distracting and also disappointing after paying so much for a new vehicle only to own something that strikes me as deficient. How can Honda produce and distribute a vehicle with this annoying and obtrusive characteristic? It is hard to believe they did not catch this and fix it during product development. I even drove a 2014 V6 Accord last week and could just make out the beginnings of this same sound, so apparently it was not engineered out for 2014. This makes me lose confidence in long term ownership of the vehicle as well as fearful of potential future transmission problems.

Any insight or other experiences will be appreciated.

What octane gas are you using? Next couple of fillups, try using the highest octane available. If the noise decreases or is gone after the lower octane gas is all flushed out of the system, you know it’s an octane issue.

Then you can try the next lower octane to find the minimum you can get away with.

In a modern engine Pinging should never occur. The knock-sensor should kick in and retard the engine enough to stop any pinging from occurring.

Without actually hearing the sound…it’s very difficult to diagnose. I suspect the dealer may be right. And the noise may or may not be harmful.

Try out what @jesmed recommends - if the noise goes away, it’s octane-related, and not transmission-related.

And every time you take it in, make sure it is documented in writing on their service order.

After being told it is “paddles” (??) within the automatic transmission vibrating or rattling" sounds fairly bogus, I am not familiar enought with the transmission to say if there are paddles in it or not, paddles seem to refer more to the type of shift control mechanism, rather than being in the transmission itself. The OP noted the other cars test driven exhibited the same symptoms, so turning the radio volume up to 11 might be the only solution!


Here’s some thoughts, based on my professional experience, including working at a dealer

If a customer complained about a noise, the first thing was to verify the complaint

The next thing was to find an identical vehicle, preferably a new one

If the other vehicle did the same thing, then it was usually deemed to be a normal characteristic

At that point, the service writer would tell the customer that we can’t fix what isn’t broken

I’m sorry if it sounds like I’m siding with the dealer. I’m just explaining things

Maybe it’s a quirk related to computer controlled ignition timing advance or EGR function and at some point when things pile up deep enough a campaign or Recall may be started to remedy the problem. That wouldn’t be a first time event.

You might try some higher octane fuel the next time the fuel level becomes low and note whether or not that makes any difference. If it does, then that could reinforce to some degree the theory about timing or EGR function. Again, theory only at this point.

Doesn’t the V6 in the Accord have the ability to run on 3 or 4 cylinders under low load conditions? My guess is that what you’re hearing is that happening.

I have a 2013 V6 Accord and do not hear any noise. Only using regular octane gas.

To be clear, if high octane get rid of the noise there’s something wrong with the knock sensor system.

Just to be clear, you have a coupe with automatic and paddle shifters; not a sedan. Is this correct?

To be clear, if high octane get rid of the noise there's something wrong with the knock sensor system

100% True.

The 4 Hondas our family had, made more noise at idle then running to move the car. The faster they turned, the smoother they seem to get. Think of the clatter a diesel makes when idling…not that your car is a diesel, and don’t worry about it. It’s the price you pay for having a reliable motor. Would you feel better if it were very quiet and gave up the ghost in 50k miles ? You have a full size car that’s capable of excellent highway performance and has a reputation from people who know, for a motor that lasts hundreds of thousands of miles. You disappointed in it ? Give it to me ! I’ll put up with the noise over a quite idling Chrysler Sebring, anyday.

I still maintain the OP is hearing the VCM kick in, and that there is nothing wrong with the car. The conditions when it happens are exactly the kind of conditions where the engine will drop to 3 or 4 cylinders and the OP experienced the same thing in 2014 model as well.

@FoDaddy - you might be exactly right, just trying to eliminate possibilities.

Another way to check it out is for the OP to borrow an identical Accord from the dealer and take it on the same route, see if it makes the same noise.

@FoDaddy, why would the VCM shut down cylinders when the OP is accelerating up an incline?

@jesmed. The OP mentioned that he wasn’t accelerating hard enough to make the transmission downshift. I suspect that the VCM is still engaged, but the noise would be more pronounced if one was gently accelerating whilst running on 3 or 4 cylinders.

@jtsanders: Sorry, it’s the 4 door and no paddle shifter

@db4690: your description is pretty much exactly what I experienced.

@FoDaddy: So, with VCM engaged and engine running on only 3 or 4 instead of all 6 cylinders, why should that produce a disagreeable rattly / knocking kind of sound? And today I was driving with the “Econ” button on…the sound seemed to be less. Does that make any sense?