Grinding noise when switching from battery power to internal combustion engine

[AluminumFalcon]

Hi All,

I just bought a used 2012 Toyota Auris Hybrid with 105k miles on it.  I really like the car, but there is one issue that slightly worries me.  If I am at low speeds (15-20 mph) and accelerate moderately, there is this brief grinding noise that comes from the back.  It only ever happens when the display on the dashboard switches from the arrow pointing from the Battery to the wheel to the pointing from the Engine to the wheel (meaning the ICE is providing the power).

It only lasts around 1-2 seconds, and when it is running on the Battery or the ICE I don't hear it.  It's just the transition from Battery to ICE, and not the other way around.

I took it to the used car dealer I bought it from, and one of the guys who worked there tried to explain that it was just normal revving sounds from the ICE.  The sound is definitely separate from the normal ICE sounds, and it sounds like it is coming from under the car behind the driver's seat, so I don't believe him.

Is this an indicator of a serious issue?  I have a warranty from the seller, but if they won't do anything, I think I'll take it to a Toyota dealer to have them check it out.  Then, if something is wrong, I'll take it to the seller with proof there is an issue.

[FROSTYBALLS]

Regardless of the warranty, you have protection as regards faults from the Consumer Rights Act 2015.

See the 'First six months section of:  https://www.which.co.uk/consumer-rights/regulation/consumer-rights-act

If there is a fault, legally the onus is on the dealer to repair and not the warranty.

[chrisgeary]

Can you record the sound? That will help. My first thought is a broken exhaust mount or something like that but without hearing it, it will be hard to pinpoint.

[AluminumFalcon]

2 hours ago, chrisgeary said:

Can you record the sound? That will help. My first thought is a broken exhaust mount or something like that but without hearing it, it will be hard to pinpoint.

I'll try to record it on my way home from work.

[jgodfrey]

If  this is the same noise as was on mine, I found it to be a corroded middle exhaust bracket that had rusted through and was making a metallic rattling noise at low speed. I cut it off and it's nice and quiet now!

[AluminumFalcon]

I managed to get an okay recording of it.  You may have to turn up the volume a bit to hear it.  I also noticed that the noise is always made when the engine reaches a certain RPM.

Auris Noise.m4a

[sportse]

I had a similar issue with my Yaris hybrid, a grinding noise every time the petrol engine started.

Turns out it had been filled with the 'wrong' oil - 5W30 instead of the correct 0W20.

Changing the oil fixed the problem.