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Discussion Starter #1
Hi All
I purchased a used 2016 highlander last weekend and over the week and a half I noticed that during idle and acceleration the v6 motor is producing very high levels of loud bass muffler sputter.. the dull loud kind with a "brrr". There isnt a metallic sound so it isn't the exhaust heat covers or anything.
I had my indie mechanic take a look with hoist and he couldnt tell anything on it running on idle...ie anything on the muffler. But I feel its distractingly and annoyingly loud inside the cabin with windows closed. There is no way that's normal. There are no lights on, and the car has a clean history on its 45k miles. Runs fine. Mileage is about 26mpg (9L/100).

Electric motor is whining a bit as well all the time which is also a significant but secondary concern I want to get to after the v6 engine and exhaust loudness.

Hoping someone can direct me to diagnosing both issues please.

Thx.
 

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Discussion Starter #3
As of motor... check invertor coolant level. That coolant is cooling down MGs. Just in case.
Thx. Had Toyota check it out and did an early pilot change as well (oakville ontario).
They called everything sounding as normal.
While I am getting used to the whine...though no comfortable with it...the rumble from engine at mid range rpms is really bothersome. I had a couple of folks look at it and visually the exhaust system doesnt seem out of place. It's just not outside I actually feel the rumbling inside with the windows up. What are my options to diagnose... other than compare with another hybrid and same MY and mileage.
 

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This:


compare with another hybrid and same MY and mileage.


As I do not recall any rumbling etc in my HiHy.
About the only thing I can think of causing this, as what you describe is power train vibration felt in the body, is bad torque mount on the R hand lower side. It's right behind the R front wheel, you can see it with slight attention. Elbow depth in. Toyota also has vibration dampeners all over everywhere, some might be missing. They look like rubber pegs or squares or rectangles on metal "legs", attached to various components. My torque mount was bad at about 80K miles.
 

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Discussion Starter #5
Still trying to find figure out a similar vehicle to compare it with. the burbling sound is only coming out of the tailpipe. No other source of the sound.
Was out on a family trip this past weekend - mileage is reasonable. No CELs.
Sound varies based on RPM. Particularly rumbling when accelerating uphill on a load - and when it comes on while starting in Park and/or charging the battery when sitting. I haven't tested it on Neutral if that makes a diff.
When momentum is driving the car and the load isn't that much I feel the burbling isn't that loud. Re the note on worn-out/broken-mounts... scary to consider/appreciate the hint... but there aren't that significant amount of vibrations felt inside the body - just enough audible burbling from the exhaust tailpipe are audible enough that they leak into the car with windows closed, particularly when there's no stereo going. The electric whine I am mostly accustomed by now - I kind of enjoy that.
The brrrr-ing not so much. I'll likely make a video and post here in the coming days.
Since the last few posts, I've had the exhaust examined at a couple of place. No issues detected.
And given that its happening when the car is in Park - And at specific rpms makes me think its something on the other end of the exhaust system (i.e. the engine). But without CELs no one suspects any intrinsic issues with Cat or the muffler.
 

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Your ICE should not even be running when in P.

Otherwise, as tailpipe is connected to cat and J pipe and all that to popwer train - look at the head of the snake for vibration cause. Can be as simple as lost vibration dampener, as Toyota has them all over everywhere, torque mount included. Some are on exhaust. Without knowing exact layout of them, though, it will be hard to find missing one.
Again, in P, engine should not run at all.
 

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Discussion Starter #7
Had a few more places check it out. Everyone has found the burbling noise normal. I feel is some sort of a resonating vibration thats louder when pulling load on ice only mode on hwy speed. Otherwise at lower rpms when its been inspected at everyone has given it a pass. Torque mounts, muffler and elsewhere, all seemed ok to them.

And enough time has passed now for me to just get used to it.

The electric motor whine in feed and regen mode are also something that Ive become used to.

Another 10-20k miles and we will likely know if it gets worse.
 
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