My 2016 mazda cx-9 (which has had 3 engine replacements due to the dealership getting substandard parts) as well as a turbo replacement is now making a high pitch whine from 3-5K RPM (sport and non sport mode). The dealership can replicate it and has used their "electric ear" to try and locate the source of the noise, they did not hear it coming from the engine, transmission or exhaust. Assumed it was a vacuum leak at first, but could not find any leaks. Dealership used smoke through the entire system as well as tape to try and ID a leak point, they did not find any. The mazda tech line released a tech bulletin regarding the turbo waste gate and that possibly being the culprit, but that was fixed when we had the turbo replaced. It's not throwing any codes or having any power issues. It's my wife's car and i have only ever taken it to a mazda dealership for service. Long story short the initial engine had a spark plug disintegrate in the number 1 cylinder and fragged it out to where it could no longer hold compression. We thought replacing the engine would be the cheaper alternative to buying a new vehicle as we had no issues with the vehicle up until that point. She is well outside of her warranty, and purchased in another state as well so lemon law probably does not apply. If anyone has any information of has experienced a similar issue with their CX-9 I would greatly appreciate hearing about it. I have a case open with mazda customer service right now to try and see where we go from here.

 

The engine sound or better short run sound only playback totally unidentifiable. Sorry but these sound bites are not very helpful 99% of the time.
You should be lucky to have a dealership that actually has a rare diagnostic tool as a "electric ear". It is not required by any platform except ford and that was only for a few years a decades ago. I would like to read the wastegate info you read because wastegates do not make that sound. And as always TSB are for the dealership, written for the service departments not really for generally public as they state on every page of them. To many IMHO owner service hypochondriacs.

By what you posted I think you have well used up the system for warranty as well courtesy service with Mazda. And no in Nevada (Nev is very close to my state (2 hour to reno) and Las Vegas is a nice weekend drive and stay getaway ) the lemon law ( i have a copy of CA, WA and NV here in the shop and as I am reading your post would not apply to your current concern. I am surprised you got coverage from the spark plug. Mazda does not make spark plugs and what you described depending on the brand happens because of the sheer number of manufactured spark plugs. But I can tell you if i were the one looking, I would have found the real cause of the spark plug failure and I bet it was not a defective spark plug. But that water under the bridge now you get the engine covered from either the dealership or Mazda or a % of both?

My strongest suggestion is if you have created a rumor with your dealerships service department don't blow it. I am sure that if you handle it friendly as I am sure you have, they will either eventually find the mystery sound or if anything else it is added to your Mazda VIN service record. Each time you visit a dealership for service that inform is applied to your VIN.

I would have liked to have seen the actual video to go along with the sounds when you throttle up like you did which is not really what would be considered a daily driven vehcle activity there are going to be changing sounds with all kinds of effluences?

 

Welcome to the forum

 

So we didn't get coverage for the spark plugs, we paid out of pocket to have the engine replaced. First engine died at about 103K miles. Plugs were replaced every 40K per the maintenance schedule, three other plugs were still in good working order. The video was just an example of the sound, and its heard in and out of sport mode. The two other engines were replaced due to defects with both, one we had to also come partially out of pocket for due to the defect being found slightly outside of the 12k/1 year warranty. But we had brought our concerns up to the dealership prior to the warranty expiring. Honestly, yes, we have been hypochondriacs with the vehicle due to multiple failed engines. I don't have the waste gate service bulletin, but regardless, the new waste gate should have fixed the issue. I also don't know what you mean by causing rumors. Even the mazda tech line is stumped. She's drivable but more so curious if anyone else has had a similar issue to troubleshoot the cause of the problem. The sound has also gotten worse since its been at the dealership.

 

The Mazda tech line has some basically qualified individual that do the best they can like a forum in helping people with issues based on their description. Ultimately a vehcle must be in the physical presence of the person Diagnosing the issue.
As for how many engine issues you had taken care of, ok that about all you can say they were taken care of. The actual details I do not think were officially found. Dealership rarely are given funds to tear down an engine to verify. Normally thye will review what the dealerships finds and what they legally need to cover and what they will extend as a courtesy to include above the large requirements. I don't care who suggested what the failure were I know that no one tore the engine(s) down.

As for you suggesting the sound is from the Turbo based on what experience with turbo chargers do you have. They don't usually that sound I herd in your video and as you described when it happens. But here again I am not physically diagnosing your Mazda. And you had Mazda service hear the noise which even less experienced "mechanic" would have known if it happened in the area of the Turbocharger.

I am trying to help you so debating defending or arguing with me is not productive not to mention we don't have close to the same experience level in this field of Q&A? But don't take offence this comes up often of a couple forums I belong to and participate on.

ASE