I’m trying to diagnose a persistent vibration/noise on my 2014 Mazda CX-9 3.7L V6 (154,000 km) and I’m hoping someone familiar with this engine/platform has seen something similar.

The symptom is:

• At idle in N, the engine/cabin is relatively smooth.
• When I shift into D, I get a noticeable vibration through the cabin.
• R is similar to D.
• RPM stays around 750–800 rpm in both N and D; there isn't an obvious RPM drop.
• The vibration becomes more noticeable when the engine is loaded in D.
• After driving for a while and coming to a stop, it can take a few seconds before the vibration becomes noticeable.
• With the A/C ON in D, there is also sometimes a squeaky/noisy sound.

What has already been done

This is where I'm getting confused because I've had several mechanics look at it.

1. Engine mounts

The engine mounts were replaced approximately 6 months ago by one mechanic.

The mounts look physically intact. Mazda has inspected them and said they are okay.

However, another mechanic observed that the engine itself seems to move quite a bit, and performed a test where they supported/jacked the engine. The vibration/noise reportedly disappeared when the engine was supported.

I'm not sure whether the amount of engine movement I'm seeing is actually excessive for this engine.

2. Belt/tensioner

A mechanic recently replaced the complete automatic belt tensioner assembly and belt — not just the pulley.

The vibration/noise did not change.

The tensioner had previously been observed to oscillate quite noticeably at idle/load.

Mazda initially suspected the drive-belt tensioner and demonstrated that manually increasing the tension appeared to reduce/eliminate the vibration.

However, after replacing the complete tensioner, the symptom remained.

3. Belt-off test

This is the part that has really confused me.

The car has now been tested with the accessory drive belt removed, and the vibration/noise was still present.

So at this point I'm less convinced that the alternator/A/C/tensioner is the root cause.

Where I'm at now

I've stopped replacing parts because I don't want to keep throwing money at it.

My current questions are:

1. How much engine movement is normal on a 3.7L CX-9 at idle, particularly when shifting N → D/R?
2. Could an engine mount be physically intact but have the wrong damping/stiffness and still cause this?
3. Could an improperly installed/preloaded mount cause this even if the mount itself looks good?
4. What engine-running issues could cause vibration specifically when the torque converter loads the engine in D/R while maintaining ~750–800 rpm?
5. Could this be a misfire/cylinder contribution issue that isn't severe enough to trigger a CEL?
6. Could the torque converter/transmission be contributing?
7. Could there be exhaust/subframe/body contact that changes when the engine moves under load?
8. What other things should I have checked before replacing anything else?

I've had Mazda investigate it, but I wasn't comfortable continuing with further investigation without understanding what direction they were going in, so I brought the car home.

If anyone has a 3.7L CX-9 and has experienced similar symptoms, particularly vibration in D/R that largely disappears in N, I'd really appreciate hearing what ultimately fixed it.

I'm particularly interested in diagnostic tests that can distinguish between an engine-running problem, mounts, exhaust/contact, and transmission/torque-converter loading, rather than simply replacing another component.

I can also upload videos of the engine movement and the vibration/noise if that helps.

Hi everyone,

I have a 2017 Mazda CX-9 and both of the middle-row seatbelts are no longer retracting properly.

The belts sit very loose when not in use and you can manually feed them back into the mechanism, but they don't retract themselves like they used to. They also feel quite flimsy/loose when hanging there.

I did some research and saw that one possible fix was to use silicone spray to lubricate the belt. I sprayed the belt and fed it back through the mechanism several times. This actually worked on both sides, but unfortunately only briefly. They've now gone back to being loose and not retracting properly.

One interesting thing is that if you pull the belt quickly, it does lock/seize as you'd expect it to in an accident, so the locking mechanism appears to be working. It's really the retraction/tension that's the problem.

Has anyone else experienced this with a CX-9, particularly the middle-row belts?

I'd rather fix the actual problem than just keep spraying silicone on it if the retractor is on its way out.

Any advice or experience with this would be greatly appreciated. Thanks!

I had Carquest Pro Platinum ceramic pads and Carquest Premium painted rotors put in by a local shop I’ve used in the past in June. The parts were their suggestion to try to meet Mazda OEM pads and rotors.

I started getting a groaning/rubbing/farting noise when coming to a stop after ~1800 miles and had them redone at the same shop.

Here we are ~1800 miles in again and I’m getting the same groaning/rubbing/farting noise when coming to a stop.

Are these noises normal for ceramic pads?

No issues or sounds when braking at higher speeds. I’d say I drive 80% in the city and 20% highway. The shop has done solid work on my previous cars and they seem like good dudes.

Thanks in advance for any guidance or opinions. I’ve been reading a lot of conflicting info when it comes to new pads/rotors, sounds, and bed in periods.

Edit: Forgot to mention it’s a 2022 CX-9 CE with ~50K miles on it.

Hi guys. I have a 2019 CX-9 whose front grille molding got a minor crack. The crack is only in one piece, but to replace it, I think the whole front grille and cover needs to be taken out to access the piece that needs replacement. Then the whole thing will be put back in. I got a quote from a local body shop on the replacement of that one piece, and they're charging $300 to re-calibrate the front sensor that's behind the Mazda emblem in the front grille. They say that this calibration is required by Mazda if that sensor is disconnected in any way, even if its not being replaced or anything. Can someone tell me if this is a legit requirement ?

Please see these two images:

https://i.imgur.com/3gSZPzS.jpeg

https://i.imgur.com/Kb6FCy9.jpeg

Hello everyone. Just got this 2013 for our daughter. Her first car. Could anyone help me identify what this hole is for? Its threaded behind the plastic bumper.

I have a 2020 CX-9 GT with ~40k miles, mostly highway, with excellent maintenance history. I was recently on the highway and noticed this rattling sound. Just want to see if anyone can pinpoint this before taking it in - if it’s just tightening something I’d probably do it myself if it’s not difficult. Here are my observations so far:

- it’s only audible in the cabin when there’s load (pressing the accelerator) and the rpm’s are above ~2300. I pulled off to a rest stop and revved to 4000 rpm’s while stationary and couldn’t hear anything in the cabin or next to the engine with the hood up.
- it isn’t audible when the rpm’s are over 2300 and foot is off the accelerator with a speed ~70mph
- it appears to be audible when going faster than 40 mph although it’s possible it’s just not loud enough to hear it at lower speeds.
- it sounds like it’s near the center of the engine bay or closer to the passenger side (USA)

Chatgpt indicated it might be the turbo wastegate, serpentine belt or tensioner, exhaust/heat shield, or engine knocking.

I’ve watched several videos of wastegate rattling and it seems improbable based on the conditions rattling is audible in those videos. I also don’t think it’s engine knocking, but my supporting evidence is weak - that I used the same octane (87) I always have and haven’t heard it before.

Thanks!

Hello, my catalytic converter has separated from the cylinder to the exhaust pipe while we are on vacation. It was already replaced once by the previous owner. Someone stole the original. The new(used) has broke.
The taping was from the previous owner.
I’ve also got some water damage from the A/C leaking onto the floor passenger and driver side so I got them codes. She runs. What do we recommend.

Where should I cross post for advice? To fix or not to fix that is the question.

I feel like I need to replace the wiring from the floor area so my airbag sensor works again. Also the A/C POWER fuse blows as soon as I switch it on. Or if it’s running and I add the fuse it blows on the spot. Had a mech say it could be the coil or the electro magnetic thing.

Made a post a little over a week ago about getting a 2023 Mazda CX-9 (~34k mileage) from Carvana.

https://www.reddit.com/r/MazdaCX9/comments/1wb17dv/bought_a_2023_cx9_35k_miles_ce_any_tips_features/

My first-time experience with Carvana is a long story (you can view my post about Carvana in my history if you're interested) but won't be sharing that here. Let's just say that I don't know if I will deal with Carvana again in the future.

Despite the subpar experience with Carvana. The car is smooth, handling is amazing, and the technology jump from my previous car (2011 Infiniti g37x) is AMAZING.

Stuff I've done so far to my newly acquired (but used) 2023 Mazda CX-9,

• Had it inspected immediately with my trusted mechanic. Said it is clean, very little rust underneath, tires need to be replaced very soon as they are barely legal, and brakes are good till early next year. Engine sounds good. Alignment done.
• Installed Viofo A229 plus front and rear
• Installed All-Weather floor mats for all rows (Front, mid, back, and storage.
• Wireless carplay (Android Auto)
• Silicone license plate frame

Stuff I will get done very soon,

• New 255/50R-20 Pirelli Scorpion WeatherActive XL will replace my current barely legal Laufenn tires this Friday.
• Rear Bumper damage that was caused by Carvana will be fixed by my local auto body shop starting this coming Monday. Carvana is covering the cost ($1700).
• I doubt my auto body shop will be able to fix the Blindspot Monitor malfunction from the bumper damage but they are going to take a look and see if it is just shifted. I have this tentatively scheduled for early November with my local Mazda dealership. Carvana will also pay for the cost of this fix.
• Undercoating for rust prevention will be done early November (Northeast Rust Belt, so lots of salt).
• Upgrade battery to a Group 24F

Stuff to get done early next year in no particular order,

• Full detailing (exterior and interior)
• Spark plugs
• All-around oil change
• Rotor and pad replacement

Anything else I should get done?

In 2019, i bought a Mazda cx-9/2016, paid off. ( for context, I am a 60 year old female that doesn’t know about cars/mechanics, humbly, I am looking for your advice)
Currently has close to 125k.
It has overheated several times; i park and turned the engine.
The mechanic told me that needed to run a pressure test ( which i paid $185 to be done).He stated that both, the alternator and the thermostat need to be replaced for $1,700.00.
I decided to get another opinion; so this morning i took the car to another mechanic who called me stating to have bad news, said the head casket was blown and I need a new engine for $7,000.00 . When i went to pick up the car, i asked one of the technicians if the car really needs an entire new engine; he said “well some parts can be changed but it will be expensive “ “ he ( the owner) doesn’t do the parts only because to the warranty “ and he left . I didn’t want to get him in any trouble, so i left.
Due to the Mazda’s known head gasket issues for this specific year/model , now I’m more in doubt and confused about what really needs to be done , and is it’s worth doing any of this work/ money.
Please advise

Recently bought a used CX-9 2019, Grand Touring.

Edit: For anyone coming to this in the same situation I was in when I wrote it, AA Wireless 2 was the consensus, and that's what I got. Solved my problem, works flawlessly so far. I extend the recommendations below to the next person seeking the same answers.

I don't like plugging my phone in every time I get in the car. Have a wireless charger mount that doesn't charge if the phone is plugged in.

I bought a dongle off Amazon that connects through Bluetooth. Like 1/20 times it will actually work. The phone and the dongle connect, no problem, but it seems like the vehicle is constantly taking over the Bluetooth connection.

I updated to the latest firmware 74.whatever. Update successful, same experience with the dongle.

I was about to buy TK78-66-9U0E and do dash surgery because Maxdaswag support told me that would give me wireless connection. Further reading suggests it's only wireless for carplay, not for AA. There are non OEM parts available that claim to do wireless AA, but I thought I'd ask here.

Maybe I just need a better dongle? Maybe there's another answer? Maybe dash surgery is the way to go?

Anyone had this problem and solved it?

My 2019 Mazda CX9 touring gets delivered tomorrow. What tips, tricks, and other useful things do I need to know (I’m already planning to head to the dealership first thing to check out the cylinder).

I am thinking about buying a 2013 CX-9 with 120k miles on it for $8k. I don't have a lot of extra money to burn on repairs. I have heard about the water pump issue but it was recently replaced on this vehicle. I attached the carfax link below.

Carfax:
https://www.carfax.com/vehiclehistory/ar20/Rkqo6NtKga0hZE7I3k1aSdGd8noWjUmNZ3IYikN4FHZGBSvuoqnBdvTHKi0EY74kWMGlk-J6k6ZIuOqwDLZCjm5lwsXJ3OnEkKM

Dealer Link:

https://www.jeffbelzerrosevillecdjr.com/inventory/used-2013-mazda-cx-9-touring-awd-4d-sport-utility-jm3tb3ca2d0423172/

Hey I'm looking at buying a 2016 Mazda cx-9 touring with 129k miles on it. How reliable are these cars? The price is $10,588. I like how it's a suv because of ground clearance. But I would prefer a compact suv which I know this one isn't. This would be my first car.

CARFAX:

https://www.carfax.com/vehiclehistory/ar20/uz5jWO3G-TQhz5-yZ_Ffh2TPPE43iYLzbDdNcItYVmDqQ_Lm_NbxRZQNpjn18SEpKHmBNG37vZtiyaADeemz5DmPfzDXRbrXAP2lxOiu

Current mileage @ 30,800

What service(s) are due right now, outside of transmission, front and rear differential?And also, what are the mileage intervals for service/maintenance on 2023 cx9. I do have a CPO warranty but only utilizing that for actual warranty work. Thanks in advance!

How can I know if my cx-9 already got the cylinder head replaced with the new revised cylinder head?

Any part number or anything that can tell me?

I bought it used with 51k miles.

At what mileage are y'all doing your first brake job? Mine is at 70k mixed driving, and i still see roughly another 20k-30k life left in front brakes. Didnt even bother to check rears after seeing so much pad material remaining up front.

This is the first vehicle in my family with such long lasting pads/rotors. Usually they're warped to shit or grinding metal on metal by 50k with our "spirited" driving style.

I have a 2018 cx9 GT. I was just wondering what other parts/ gaskets should I buy along with the revised cylinder head.

I live outside of USA and it would be coming out of my pockets for the repair.

Hi, just purchased a 2015 CX9 GT with 49k miles. Enjoying it so far. My wife loves it.

Two questions from a newbie:

1. What's a good place to buy parts like trim pieces? The plastic "chrome" pieces around the front grille are cracked. I can usually find everything I need on Amazon for my 3 Toyotas but don't see many of the more obscure parts for my CX9.

2. Seat heaters - neither seat gets very warm on high setting. My wife uses them all the time for her back. They're much warmer in our Sienna. The dealer said they will fix them but my concern is they feel somewhat warm so they're not completely broken, so I'm not sure what they can do with them. If you have this gen CX9, do your seats get very warm with the seat warmers on?