"Harmonic vibration", as in an unbalanced rotating part?Originally Posted by Puyapim
Harmonic vibration occurs when rotating or reciprocating masses are out of phase. They are addressed in design and wouldn’t change with temperature unless there is a lump of ice on something. It would not apply after a 25 minute drive as reported above but at minus 25 materials and fluids might do some unusual things. I don’t know about these things in detail but I am 100% certain that Mazda’s cold testing engineers do.
Thanks. I just wanted to ensure Puyapim and I had the same understanding as to what a harmonic imbalance is given his statement. It's been a few years since I took advanced dynamics in university so granted I'm a bit rusty, but like yourself I don't see how harmonic imbalance or vibration could be induced by cold temperatures.
I don’t see why not. If the fluid in the mount thickens just enough to create a small vibration that is accentuated by the stamped chassis or other components then that could be one example. I might be using the wrong term here. I’m not a engineer. Resonance might be another term that applies.
My experience with harmonic vibrations was on a ship. After much investigation it was narrowed down to a defined and narrow rpm range on the diesel mains. The solution was to not run the engines at that specific rpm. The vibration could be felt across the entire ship.
Hey guys, got word on Friday that Mazda is aware of the vibration issue in cold weather and are currently doing testing and coming up with a fix. They're hoping to have a fix before next winter, it's too late to do anything for this winter.
I'll see if I can get more info to pass along.
My dealer said the same thing to me too. I hope they get it resolve by next winter or they will have a lot of cx-5 back. This is a deal breaker in cold locations.
My background is in engineering so I know where your coming from.
Over the years, car manufacturers have used different materials to soften vibration to the cabin and within the cabin.
From my experience working on cars since the 90s to now, outside the cabin, outside the car,the dominate material used is a rubber base or something very similar. You would have these at most spots where one piece needs to move freely from another, but still be attached.
Examples,
engine -> body,
transmission -> body,
exhaust -> body,
suspension/differentials -> body,
suspension arms -> body, plus many others.
In cold temperatures it's naturally stiffer and would transmit more vibration to the cabin. Rubber base materials naturally break down with heat cycles, exposure to chemicals that break it down, and just age.
My experience with changing rubber bushings.
Older cars that we used to convert to dedicated race cars would have aged rubber bushings that created problems(another topic). We'd replace all of them with solid bushings or a much stiffer, less flexible, material than OEM. Usually we used Polyurethane so there's "some" vibration dampening and memory.
We got a better feel of the road (desired), but much more vibration was transmitted to the cabin from everywhere(less desired).
In the last 5-10yrs, there has been some impressive advancements in creating a quiet cabin and I imagine they've gone beyond the OEM rubber base material to more exotic materials or creative construction.
I had no clue Mazda used liquid filled bushings between the engine and body(which sounds great, but expensive).
If the claim is that it "freezes", then I predict it actually becomes solid (not just thick) under extreme conditions and that WILL transmit a LOT of vibration to the cabin. My guess is that what ever liquid they do use
I'm curious as to what the "band-aid", short-term solution would be and what technology other car manufactures use that are exposed to extreme colds (Alaska, Canada, Sweden, Finland, etc).
100% of the time, materials that work well between extreme hot and cold temperatures, increase in cost astronomically, if it's even possible. Usually it's more cost effective to use different materials for different environments.
I predict they will do a voluntary recall, or bulletin to the techs to replace/add blah-blah for people who have complaints, and then for the 2020 or next generation model, there's a different material for Canadian built cars with a higher price tag. I would be really impressed if a solution was already integrated into the 2019 model year truck.
Perhaps, the supplier who designed, built, and sold the liquid filled bushing to Mazda promised it reduces harmonics by xx% minimum from yy deg F/C to zz deg F/C and internally where they assemble it, Joe Assembler hates his job or is pissed at his manager didn't do his job to what the instructions say, "because it'll will work fine", "those stupid engineers don't know what they are doing", "Reduce my benefits/retirement? Screw you guys".
Therefore it's only a batch of bushings that are out of tolerance and not a poor design.
Last edited by leedar; 03-29-2018 at 08:20 AM.
FYI - For my 2017 CX-5 that was experiencing lots of vibration while the engine was cold (very noticeable at sub -15 degree celsius temperature outside), my local Dealer said Mazda Canada's fix is to to replace the lower transmission mount, which they did under warranty.
Ya there is a active tsb on this. Getting mine replaced Tuesday. 2018 gt
Also did anyone that has had this vibration, have you noticed a lack of power at all?
It's been super cold here all week and my engine has been completely and utterly dead. Feels like it's running on two cylinders. The ECU pulls timing big time at these temps until it is sure the oil temperature is normal, which takes 20-30 minutes of driving to achieve at temps like this.
My liquid engine mounts froze solid last Wednesday and the car has felt and run like complete and utter garbage ever since. I really understand how frustrated the Canadian market has been over this issue now. This car feels shockingly, embarrassingly crude and under-engineered when this condition rears its head. The little tin can Ford Escort I drove 25 years ago as my first car felt like a Lexus compared to my CX-5 driving experience this past week.
Taking off from stops is the worst of it. The car vibrates so terribly it feels like it's destroying itself. And the NOISE. Like some cheap subwoofer blasting a 70hz sine wave at full volume. Mazda is not getting nearly enough flak for this engineering gaff.
Yours too hey? Mine felt so gutless in this cold also felt like it had 50hp.
I've had this happen to a '15 and recently to my '17 CX5. Once the temp dives to -20F (-29C) the engine vibration at idle and when the auto trans upshifts below 1500 RPM is severe. A couple of weeks ago one of those polar vortex events dropped down to visit. My son was using my unheated but attached garage while he was out of town so the '17 CX5 GT was left outside unused for several days. I needed it to make a 10 mile trip and it never did stop these vibrations. I tried shifting manually to keep the revs up a bit which helped.
I also had issues with it not recognizing the NAV SD card, the front SCBS sensor reported an error and the car didn't recognize I did have my seat belt fastened.
During my meeting we parked in a heated underground garage. When I returned to the vehicle 2 hours later it was fine.
It's definitely the motor mounts but the safety gadgets shutting down in frigid conditions is a bit more worrisome.
I wonder if the frozen motor mount had anything to do with it. It*s possible the vibration caused the knock sensor to pull timing with all the vibration inside the motor it*s possible? Mine vibrated at idle so bad I thought the interior was going to fall apart and the rear view camera even vibrated lol, you could feel it while at speed but not that much more so at idle, but either way. As soon as mine smoothed our after the mount thawed a bit the power was back.
Also today was -18 and I drove a couple min the punched it to see and it had full power. The vibration wasn*t there either as it has been warmer the day before and thawed a bit. So who knows
Last edited by Zeroman; 02-12-2019 at 12:58 AM.
Got the new mount in. Way smoother even smoother then when new. Very happy!
Did they change the liquid filled mount for a traditional rubber one, or did they just re-design a new liquid mount with fluid that doesn't freeze at low temps? If it's the latter then I am definitely interested in getting mine replaced too. I was afraid they would just sub a rubber one and the NVH would be worse overall in warmer weather. As awful as this is when it's super cold have to say in warmer weather the liquid mounts are great. It's definitely the smoothest 4-cyl idle I have ever experienced in the summer, except for the A/C condenser cycling creating those little shudders kind of ruins it a bit.
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