I’ve recently had a little extra free time so I decided to try and fix a couple of automotive related annoyances I’ve been experiencing. I know that there are many people out there who are perfectly happy to turn up the radio if their car makes any funny noises, I, however, am not one of those people.
The MDX started making a grumbling/rattling noise around what seemed to be the center of the dash. When I shut off the fan and put the system on re-circulation, the noise became quieter and sometimes went away. Turning the fan speed higher made the sound less noticeable but with whooshing of the air from the system, I couldn’t tell if the sound was less or just hidden. Various combinations of switching between floor vents and dash vents did not seem to effect the sound.
My guess was that some internal component or door in the dash was broken and I was just going to have to live with it because I really didn’t want to take apart the dash. But before giving up, and because I’ve had some luck doing it in the past, I decided to look on the internet to see if there may be a TSB related to this problem. While not finding any TSBs, I did come across an interesting post Rattling Center Dash (Heater A/C Air Mix Motor) by the user 12BlueX.
Following the instructions along with watching the YouTube video made the process pretty simple. I did initially misalign the door control lever which resulted in too much heat when the system turned on but this was an easy fix by reattaching the motor with the lever engaged correctly.
Emboldened by the MDX success, I turned to to G35 with the chirping dash. Usually the chirping/squeaking/high pitched rattling seemed to come from the vents on the passenger side of the dash or behind the glovebox. Other times it almost seemed to be from the bottom of the windshield.
My initial idea was that something had come loose when the cabin air filter was changed, which is behind the glovebox. However, after replacing the cabin air filter with an OEM filter made by Nissan and installing a few zip ties to make sure everything was secure, the noise remained.
My next thought was that perhaps something had fallen into a vent. In the not too distant past, the driver side door window was shattered and glass had gotten everywhere. And while driving, covering all the vents did seem to make the sound quieter so I tried compressed air and a shop vac to see if something was in the vents. Again no success.
Once again turning to the web, I tried many, many google searches for G35 dash squeaking or high-pitched rattle which led me to suggestions that it could be the mirror or to spray the dash with WD40 or to just turn up the radio and live with it. In the end, I found the post Dash Chirping by PedalKick which suggested it was the battery. I felt this to be pretty unlikely but I went to the car and shook the battery and there was the squeak. I still couldn’t see how the sound could be so loud in the cabin but as was mentioned in the article, when I removed the cowling from around the battery, I could see the large opening in the firewall for the air intake to the heating system. After putting a little grease on the battery hold-downs and making them each fairly tight, the squeak was finally gone.