Rattle/knocking from engine (video)

[draculr]

Hi there, I've had this very intermittent engine knocking sound on my 2017 Toyota 86 (it's still under warranty so I'd like to identify what's happening so I can take it to the dealer). It happens quite rarely as in once per trip and usually doesn't happen when the car is warm, nor does it happen on a cold start.

I'm happy to have finally caught it on video! You may need to turn the volume up as it was recorded by phone from inside the car.

[ame="https://www.youtube.com/watch?v=AVJHevOBogo"]https://www.youtube.com/watch?v=AVJHevOBogo[/ame]


Does anyone have any idea what this is? Should the dealer be able to diagnose it from this video?

[ZZT86]

Manual ? Possibly clutch or flywheel.

[draculr]

Originally Posted by ZZT86

Manual ? Possibly clutch or flywheel.

Yep it's a manual sitting in neutral and I'm not holding down the clutch pedal. The noise gets worse when the a/c compressor kicks in and with it the fans so I was wondering if it's something related to the drive belt/pulleys?

[ZZT86]

If you press clutch in does it go away ? Hot idle revs are pretty low causing some vibration which transmits to the rest of the driveline including clutch & flywheel which are known to rattle sometimes especially on 1st gen Hachis.


I would say typical/normal but please get the dealer to confirm it.

[draculr]

Originally Posted by ZZT86

If you press clutch in does it go away ?

I'll will try the next time I hear the sound and see if it goes away!

[humfrz]

I'm not hearing anything unusual -


humfrz

[draculr]

Originally Posted by draculr

I'll will try the next time I hear the sound and see if it goes away!

I just ran the car until the rattling came in, it seems to take 2-3 minutes after a cold start to start producing the rattle sound. Just like you suggested it goes away after I depress the clutch.

I've booked some time in with the dealer and at least now I have some information for them.

Cheers mate!

[mrha]

Sounds to me something is loose or unbalanced.

[draculr]

Okay the dealer has reproduced the issue and has booked me in for a release bearing replacement under warranty.

I'm wondering since they have to pull the gearbox out to do the job if it's worth me having them replace the clutch itself? The part should be fairly cheap I imagine but then again the car has only done around 28,000km (17k miles).

[Tcoat]

Originally Posted by draculr

Okay the dealer has reproduced the issue and has booked me in for a release bearing replacement under warranty.

I'm wondering since they have to pull the gearbox out to do the job if it's worth me having them replace the clutch itself? The part should be fairly cheap I imagine but then again the car has only done around 28,000km (17k miles).

Unless the bearing has caused damaged to the clutch plate or flywheel I wouldn't bother. There just simply would not be that much wear at that mileage to warrant the cost.

[draculr]

So the dealer service changed the throw out bearing under warranty but it has not fixed the issue. I was surprised they thought it was the TOB since it usually makes sound with the pedal depressed I imagined?

Anyway, they want to book it in to look at again and I made them this video: [ame]https://www.youtube.com/watch?v=bGjnfPUqWoo[/ame]

It still goes away when the pedal is depressed. Does anyone have any insight into what it may be that's loose and causing this rattle?

The rattle starts occuring 5 minutes after a cold start (I just let it idle for 5 minutes) and seems to go away when the car is properly warmed up.

[humfrz]

Originally Posted by draculr

So the dealer service changed the throw out bearing under warranty but it has not fixed the issue. I was surprised they thought it was the TOB since it usually makes sound with the pedal depressed I imagined?

Anyway, they want to book it in to look at again and I made them this video:

It still goes away when the pedal is depressed. Does anyone have any insight into what it may be that's loose and causing this rattle?

The rattle starts occuring 5 minutes after a cold start (I just let it idle for 5 minutes) and seems to go away when the car is properly warmed up.

I'm going to ring up ol @Ultramaroon and ask him if this sound could be "gear rollover"?




humfrz

[Ultramaroon]

Originally Posted by humfrz

I'm going to ring up ol @Ultramaroon and ask him if this sound could be "gear rollover"?




humfrz

That's all it is. Engine labors driving the AC compressor while idling. Flywheel is as light as possible for a little 4-banger so it rattles the gearbox.

Shame on the dealer. Sad waste of money.

[Grady]

Hard to tell, Do you have a light weight fly wheel?