Strange grinding noise on cold start.

My car is 2014 Toyota Aqua with12,500kms on the odo.
I have noticed that when i start the car in the morning a strange grinding sort of noise is emitted from the engine bay.
It continues till the battery is fully charged then this strange noise stops and the engine noise returns to normal before the engine switches off.
Can some one comment pls.

Thanks

 

Thanks for your advice.
Unfortunately we dont have toyota dealer support for Prius & Aqua as these are personal imports.

You have any idea as what could be the source, otherwise the car is running fine, no warnings.

Thanks

 

Thank you for your replies;

Yes I will try and record the sound and post it on the forum.

I really dont recall if the noise was there when i got the car or not. I have a feeling that it started after i scrapped the car on a speed bump.
I plan to get the car on lift and get the underside inspected.

As regards to oil, i have recently got oil and oil filter replaced. Oil if is fully synthetic 0w-20 Kixx.

The ambient temperature these days is 30deg C.

I checked the oil and its upto the full mark.

 

I got the car on the lift, the noise comes from the transmission side.

The sounds is like a bad bearing (like that made by regular cars when the water body bearing is bad).

The noise starts 10~20 seconds after starting the car. It continues as long as the engine is running and stops few seconds before the engine shuts off. I presume the sound comes when the battery is being charged, when engine is under load.

Pressing the accelerator, brake has no effect, the sound continues.

Sound stops when car is shifted to neutral, and starts as you shift out of neutral to any gear ( P, R, D & B).

There is no warning, the car is running flawlessly, the mileage is unaffected.

Any guesses.

 

Yes, thats my impression too. May be some senior can guide me.
I have been referred to a specialist workshop, they will be visiting my home to witness the cold start.
Lets see what they find.

 

No, it did not. I know this as its only 9000kms driven when i bought it from auction. Secondly I got the maintenance record with the car which showed the inspection and oil change.

As regards to the grinding noise, the chap who came over to my house in the morning checked the car and said it seems like exhaust system rattle. So we took the car to the workshop and up on the car lift.

We kept the car running, and as the engine started they started tracking the noise. Eventually some bolts were found to be loose and the shield was rattling making horrible grinding noise.

Thankfully the car is back to its original state. Much relieved.

 

True, rather we are proactive and associate every issues critical as it pertains to a Hybrid.