Rattle Noise between 5000rpm and Redline when A/C is off

[ABQRL]

Hi all,
I'm hoping there is a Honda service tech (or even any experienced mechanic) or two out there who might have an idea of what's going on here.
I bought my new 2007 RTL back in August. Since the vehicle was new, I have noticed a strange rattling sound that appears to be coming through the firewall on the passenger side at approximately 5000rpm-redline. I don't honestly spend much time in that rpm range but when I really need to get on the gas, the noise is very apparent. It almost sounds like a bad bearing in a pulley. The only way I can eliminate the noise is to turn the A/C compressor on. The noise also goes away if I turn the temperature control dial all the way down to "Lo." Even though on "Lo" it says "A/C Off," I think the compressor is coming on, because the noise immediately goes away.
Anyway, I've had the truck in to the dealer twice this week for this problem. The first time, they took apart the entire dash and re-padded everything and tightened it all down nicely, which did take care of the airbag rattle I had. However, the other noise persists. I took it back yesterday (Thursday) and they replaced the Outer Drive Belt Tensioner. Honestly I do not know why they did this, but they did, and of course the problem is still there.
I'm starting to suspect a problem with the clutch mechanism that engages to turn the A/C compressor on and off. Obviously, the A/C pulley is always turning when the engine is on (rattle rattle), but the clutch is only engaged when the A/C is on (no rattle).
I'm just tired of going back to them time after time, so I'd GREATLY appreciate it if anyone here who might have knowledge of these types of issues could arm me with a list of possible causes to take into the service department when I go back.
Thanks to the friendliest Ridgeline forum on the net!
-Dustin

[Pizza Man]

ABQRL wrote (View Post): › docWrite("quote")Unfortunately, in the eyes of the dealer, I really don't know anything because I'm just a stupid customer with a warranty issue that they will have to fix for free.
Hi Dustin.

The warranty repair is free to you, but the dealer does get paid from Honda. It is probably at a rate less than the dealership shop labor rate, but never the less he gets paid.

I'm no mechanic, but it sounds to me your logic is fine. Has the service tech heard the noise? Have you taken him for a ride to demonstrate for him? Keep after them, they'll get it right.

[ABQRL]

Pizza Man wrote (View Post): › docWrite("quote")
Have you taken him for a ride to demonstrate for him? Keep after them, they'll get it right.


Yes, I took one of the service techs for a ride after the 1st time I had the truck in and it didn't get fixed. When I took it back the second time, I asked that that tech be the one to work on the vehicle. Of course, they said "sure," but in the end, he didn't work on it. I went back again that afternoon to take my service adviser for a ride, but I think I had the A/C on because it didn't make the noise (it was probably set to "Lo." At that point, I didn't realize that setting it to "Lo" would also make the noise go away). So I'm going back again today to let the service adviser hear the noise. Hopefully they'll get it right this time. I'll be sure to post what happens next.

[ABQRL]

Pizza Man wrote (View Post): › docWrite("quote")
ABQRL wrote (View Post): › docWrite("quote")Unfortunately, in the eyes of the dealer, I really don't know anything because I'm just a stupid customer with a warranty issue that they will have to fix for free.

P.S. I edited the original post to remove this statement. Boy, I must have been in a really bad mood to write something so negative. Sorry! :lol:

[ABQRL]

Does ANYONE else have this issue with their RL?
I've had the truck in twice for this problem and they haven't found it. Took the service adviser for a ride and he heard it... said he wasn't sure what was causing it but would take a couple other RLs for a ride and see if they had the same noise. He said one of them did, so I'm wondering if anyone else here has noticed it.
I realize all cars have their own quirks, but this is really strange.
Should I even bother going back to the dealer, or just live with it?
Any thoughts?
-Dustin

[ABQRL]

Alrighty,
Well, since nobody has replied, I'm guessing this is a rare issue, which means it's all the more important to get the dealer to fix it rather than just live with it.
I've got an appointment to take the Ridge in next Tuesday. They're giving me a loaner car, and I told them to take as long as they need to get the dern thing fixed. I'll be sure to post the outcome here.
-Dustin

[DopplerDon]

Actually I hear something like a metallic vibration/resonance behind my glove box when ringing it out. Never really associated it with what you are speaking of until now. Let me know what they find.

[ABQRL]

Going into day 3 of work on my Ridge today. Spoke with the service dept last night. Yesterday they spent the day replacing some exhaust components that were rattling apparently (I never heard them). They're now looking to the heater core as the source of the noise. There is a valve in there that shuts off the flow of coolant to the core under 2 conditions: 1- Anytime the A/C compressor is on, and 2- When the temp control is set to "Lo." They now believe that the flow of coolant is what's causing the noise, and that with the dash disassembled, it sounds more like a "gurgle" than a "rattle." So, they're getting close to finding what's wrong.
I'll post another update once the work is done.
-Dustin

[ABQRL]

DopplerDon,
Sounds like you've got the same thing going on. It's been frustrating because it seems to be a rare issue and I could only find one other forum post anywhere (for any Honda V-6) where someone complained of this issue. It was on an Acura-forum post some years ago, but in that guy's case, the dealer never found the cause. I'll be sure to post the full report once the work is done so if you decide to take your RL in, you won't have to wait for days like I have.
-Dustin

[ABQRL]

Well, the work is done, the votes are in, and the Ridge is back in my tender care.
My dealer spent 2 1/2 days working on this, with multiple phone calls to and from Honda, and they finally determined that the noise is indeed being caused by the flow of fluid through the heater core.
The noise cannot be resolved. Honda is aware of the noise but does not consider it an issue because it is inherent to the design of the heater core in all Ridgelines, and it is not considered a design flaw. Most people do not spend more than a few seconds in the 5000rpm-redline range during any given drive, so I suppose that's why more of you have not noticed it. I have adjusted my driving habits as of late (mostly because flooring it burns a lot of gas) and the noise does not really bother me anymore.
In any case, if anyone else is considering taking their RL to the dealer for this issue, I'd say go for it. They won't be able to fix it now, but maybe if enough people get after Honda about it, they'll redesign the core and issue a TSB or something. Then again, maybe not.
Oh, by the way, they also replaced the intermediate exhaust heat shield. I guess there's a TSB out for that, though.
Either way, still loving my Ridge... and Honda.