Weird noise from bottom

[rickyf10]

I’ve recently notice that there is some strange noise coming from bottom when I full throttle. It sounds like squeezing a pop can and lasts very short that i cannot even record it. It is noticeable only when the car in low rpm and low drivelogic. I first thought it was coming from rear diff but after I have my buddy checked and changed the fluid, nothing helped. Anyone has idea?

[M5Rick]

Originally Posted by rickyf10

I’ve recently notice that there is some strange noise coming from bottom when I full throttle. It sounds like squeezing a pop can and lasts very short that i cannot even record it. It is noticeable only when the car in low rpm and low drivelogic. I first thought it was coming from rear diff but after I have my buddy checked and changed the fluid, nothing helped. Anyone has idea?

You shouldn't apply full throttle when car is travelling in a very low gear, change down to a higher gear first or depress the throttle gradually until the revs rise. You may have poor quality fuel.

[rickyf10]

Originally Posted by M5theonlyone

You shouldn't apply full throttle when car is travelling in a very low gear, change down to a higher gear first or depress the throttle gradually until the revs rise. You may have poor quality fuel.

Sorry for my bad expressions
When I put on gas at high gear (low rpm). The throttle angle doesn’t trigger downshift and whine begins. Once I downshift and rev higher, no whine (Or maybe I can’t hear cuz of high rev noise)
For fuel quality, 91 shell is my choice. I dont really think it’s a fuel quality related
But thanks for bring it up

[SapphireM5]

Originally Posted by rickyf10

Sorry for my bad expressions
When I put on gas at high gear (low rpm). The throttle angle doesn’t trigger downshift and whine begins. Once I downshift and rev higher, no whine (Or maybe I can’t hear cuz of high rev noise)
For fuel quality, 91 shell is my choice. I dont really think it’s a fuel quality related
But thanks for bring it up

Differential? Try to do a steady speed on the highway maybe around 50-60mph. Lightly hit the throttle then let it coast. Does the noise come and go? Could be the rear differential.

[rickyf10]

Originally Posted by SapphireM5

Differential? Try to do a steady speed on the highway maybe around 50-60mph. Lightly hit the throttle then let it coast. Does the noise come and go? Could be the rear differential.

No whine can be heard at that speed. It usually happens below 30kph which means sometimes starting from the rest with enough gas will make that noise.
Also lightly hit the throttle will not whine, it only comes at low rpm and large throttle angle. Could it be driveshaft???

[M5Rick]

Originally Posted by rickyf10

No whine can be heard at that speed. It usually happens below 30kph which means sometimes starting from the rest with enough gas will make that noise.
Also lightly hit the throttle will not whine, it only comes at low rpm and large throttle angle. Could it be driveshaft???

I was about to say, if it's more of a whine a bearing in g/box or prop/drive shaft may be showing the first signs of wear by coming on and will only get worse as time goes on.Whats the mileage?
I suggest a rolling road test and evaluation to pinpoint the cause to be sure.

[rickyf10]

Originally Posted by M5theonlyone

I was about to say, if it's more of a whine a bearing in g/box or prop/drive shaft may be showing the first signs of wear by coming on and will only get worse as time goes on.Whats the mileage?
I suggest a rolling road test and evaluation to pinpoint the cause to be sure.

90k kms now. I properly will have my buddy fully checked the vehicle and see what’s going

[Mr. M6]

i have whine at speed 100km and more and when i let off, i hear little whine noise, took the car to dealer and checked, they told me differential will be replaced under warranty, i will check if the noise will go or still there later...

[M5Rick]

Originally Posted by rickyf10

Sorry for my bad expressions
When I put on gas at high gear (low rpm). The throttle angle doesn’t trigger downshift and whine begins. Once I downshift and rev higher, no whine (Or maybe I can’t hear cuz of high rev noise)
For fuel quality, 91 shell is my choice. I dont really think it’s a fuel quality related
But thanks for bring it up

''Throttle angle doesn't trigger downshift'' (in auto yes) That is a fault and the can crunching noise may be the engine strangling itself with throttle actuator struggling. You may have a problem with the throttle KICKDOWN actuator then.