2017~2024 Mazda CX-5 acceleration noise at low revs

[Mramalho]

Hello!

I have a 2018 Mazda CX-5 2.2 Diesel Skyactiv AWD. It makes a very annoying noise when I accelerate hard at low revs. The lower the revs and the more I floor the gas pedal, the louder the noise is. It's clearly noticeable between 1500 and 2100 rpm, I can't hear it above that. The noise gets louder when the air conditioner is turned on.

I took it to a Mazda workshop and they don't know what it is. They just told me to go back if it gets louder or the car isn't working properly.

I recorded it, you can hear it below at 00:07 seconds.

 

[Snorting2.5]

It's a sound which indicates that, you SHOULD NOT be forcing the engine to "accelerate hard" from relatively low RPM's. Some more responsible driving habits will fix your problem very quickly!

 

[skid00skid0]

That's a horrible recording...

Might be the tires deforming while accel. Were you at WOT?

 

[Mramalho]

It's a sound which indicates that, you SHOULD NOT be forcing the engine to "accelerate hard" from relatively low RPM's. Some more responsible driving habits will fix your problem very quickly!

That is not very helpful. And I said accelerate hard, but for example, when I'm driving up the garage ramp (relatively steep) I hear that noise all the time. In first gear. There's really no other option other than pushing the pedal.
I know this is not a normal sound, so telling me to not accelerate hard is not helping identifying what it is.

 

[Mramalho]

That's a horrible recording...

Might be the tires deforming while accel. Were you at WOT?

What does WOT mean? Any suggestions on how to make a better recording?

 

[Koko_Bandit]

Wide Open Throttle

 

[HyFlyer]

What does WOT mean? Any suggestions on how to make a better recording?

WOT = "Wide Open Throttle"

I listened to your YouTube video recording. I can't discern anything from it. Is your 2.2 diesel a manual transmission or automatic?

I understand what @Snorting2.5 is trying to relate to you and I believe he is (in his own way) trying to be helpful to you. ... that you're trying to operate your engine at too low of an rpm (1500-2100) for a heavy throttle position. Which would be true of a gasoline engine. I think he may not have picked up on you having the 2.2 diesel. The skyactiv diesel does have quite a bit of torque at lower rpm although not the same as the torque curve of a large commercial diesel.

The sound you're hearing could be vibration and harmonics of the harder hitting power pulses at the slower rpm.

If your cx5 has an automatic transmission, it should slip a bit by itself to raise the rpm on its own. If you have a manual, your choices are use a lower gear or if you're in the lowest gear, increase your speed enough to operate at a higher rpm or slip the clutch a little if you can't increase your speed.

 

[erhayes]

why are you beating the engine at so low of revolutions. Use a lower gear or black off the throttle.

 

[Mramalho]

WOT = "Wide Open Throttle"

I listened to your YouTube video recording. I can't discern anything from it. Is your 2.2 diesel a manual transmission or automatic?

I understand what @Snorting2.5 is trying to relate to you and I believe he is (in his own way) trying to be helpful to you. ... that you're trying to operate your engine at too low of an rpm (1500-2100) for a heavy throttle position. Which would be true of a gasoline engine. I think he may not have picked up on you having the 2.2 diesel. The skyactiv diesel does have quite a bit of torque at lower rpm although not the same as the torque curve of a large commercial diesel.

The sound you're hearing could be vibration and harmonics of the harder hitting power pulses at the slower rpm.

If your cx5 has an automatic transmission, it should slip a bit by itself to raise the rpm on its own. If you have a manual, your choices are use a lower gear or if you're in the lowest gear, increase your speed enough to operate at a higher rpm or slip the clutch a little if you can't increase your speed.

If you pay close attention to the video, with headphones, if you have them handy, you'll hear this *insert word* sound (I really don't know which word describes it) starting at 00:08 and ending at 00:11.

Fair point, I forgot to mention that it has an automatic transmission. I do notice it slip by itself when I have to drive slowly uphill in 1st gear. So I guess that's what you mean by "slip by itself to raise the RPM".

 

[Mramalho]

To clarify, I'm not on wide open throttle when the noise is audible.

 

[HyFlyer]

Yes, I had listened to the video using earbuds. I do hear the lower pitched rumble at the timeframe you have indicated. I don't hear anything I would describe as unusual though. It just sounds to me like an engine under load.

So, you have a 2.2 diesel with an automatic transmission so it's not an issue of the motor "lugging" at too low an RPM as @Snorting2.5 and @erhayes have opined. 1500-2100 rpm is not (IMHO) too low for a diesel.

@Mramalho , is this a new sound that hasn't been occuring previously? Or a new car for you? New to diesels?

 

[Mramalho]

Yes, I had listened to the video using earbuds. I do hear the lower pitched rumble at the timeframe you have indicated. I don't hear anything I would describe as unusual though. It just sounds to me like an engine under load.

So, you have a 2.2 diesel with an automatic transmission so it's not an issue of the motor "lugging" at too low an RPM as @Snorting2.5 and @erhayes have opined. 1500-2100 rpm is not (IMHO) too low for a diesel.

@Mramalho , is this a new sound that hasn't been occuring previously? Or a new car for you? New to diesels?

So, the story of the car: I bought it second hand last August with approx. 44700mi on the clock. I didn't notice the noise when I was test driving it (but I may have missed it because I was paying attention to a lot things while driving it). What I did notice in the end was that the AC was not working.

They fixed the AC and I picked up the car a few days later. When I drove off I noticed this noise.

A couple of months later I took it to a Mazda workshop (I'm living in Germany at the moment but I don't speak German). Communication was not very easy but in the end they wrote that they suspect that the turbocharger is the cause for the noise, but it was unclear to them and needed to be further diagnosed.

I think that a broken/defective turbocharger doesn't make a noise like that, so it kind of made me lose trust in that workshop.

The car now has 50950mi, the noise seems to be louder than before but doesn't seem to affect car performance. My fear is that this will just get worse and cause severe damage to something if not timely fixed or leave me stranded on the highway some day.

A couple more things I notice:
- The noise gets louder/more annoying if the AC is on
- In rare occasions, when I step on the throttle there is absolutely no noise. Then if I stop at a red light I'll hear the noise again when I drive off.

I'm not new to diesels, I have a Toyota D-4D 1.4 and I have driven a lot of different cars to this day. I have never heard such a noise.

 

[Conrad 16.5]

If you pay close attention to the video, with headphones, if you have them handy, you'll hear this *insert word* sound (I really don't know which word describes it) starting at 00:08 and ending at 00:11.

Fair point, I forgot to mention that it has an automatic transmission. I do notice it slip by itself when I have to drive slowly uphill in 1st gear. So I guess that's what you mean by "slip by itself to raise the RPM".

I listened with ear buds, and I do believe that I hear the sound you're referring to. Kind of a 'boop boop boop' sound, higher in pitch than the surrounding noise.

No idea what it could be though. The car runs fine?

 

[PTSanchez]

more things I notice:
- The noise gets louder/more annoying if the AC is on

Huge red flag, right here.
Have you scanned it for DTCs?
Also suspect worn bearings in the A/C compressor, or bad A/C clutch hub.
Could you perhaps make another video for us: engine running, but A/C turned off. Then turn on the A/C - so we could hear the difference?

Here's what a typical hub looks like: A/C clutch hub. - Google Search

 

[Mramalho]

Huge red flag, right here.
Have you scanned it for DTCs?
Also suspect worn bearings in the A/C compressor, or bad A/C clutch hub.
Could you perhaps make another video for us: engine running, but A/C turned off. Then turn on the A/C - so we could hear the difference?

Here's what a typical hub looks like: A/C clutch hub. - Google Search

I haven't scanned it for DTCs yet. You say it's a huge red flag because it could a problem with the engine?

If it's worn bearings in the compressor or bad clutch, would it still make this noise when AC is off?

I'll make a new video.

 

[PTSanchez]

THIS v v v is the big red flag I noted:
- The noise gets louder/more annoying if the AC is on.

Re: "would it still make this noise when AC is off?"
Yes, it could - as long as the engine is running.

The serpentine pulley on your compressor clutch has an internal bearing which is spinning whenever the engine is running, but the compressor is not engaged until A/C is turned on. See pic below.

 

[Mramalho]

Hello again,

Sorry for leaving you hanging. I had to leave mid-July and had no way to record a new video until today.

I tested with and without A/C today and I couldn't hear the difference. Maybe the other times I noticed the noise getting louder after turning on the A/C or was paying more attention to it. Or I was just unlucky today.

While I was away I realized that the sound capture from one of my other devices seems to be better, so I went for a drive today and recorded the full thing. You can find the links below to the full recording but with different start times, where the noise is audible.

Listen until 2:45

Listen until 7:40 - in this part I was able to reproduce a rare grinding noise that happens very rarely (I think it happened four times max in 1 year since I got the car). Unfortunately the audio quality is not good enough to pick it up. It happens at 7:34.

Listen until 8:25 - in this part, after letting go of the gas pedal, I could hear an helicopter noise (which I heard in a previous car I had and it was one of the wheels' ball bearings that needed to be replaced)

Do you think this could still be related to the A/C compressor clutch?

Could this be gearbox related? Some worn out/damaged ball bearings?

Could this be coming from worn out/damaged ball bearings on one of the wheels?

I'm sorry for all the questions, but I'm getting paranoid. I drive with my family quite often on highways/high speed and I don't want this noise to go from just annoying to something that could cause an accident.

 

[Mramalho]

Just one more video, post with more than 3 media items are not allowed:

Listen until 16:20 - this was with the A/C on for a few minutes. Couldn't tell the difference.