Do the rough cold starts hurt it?

How many miles on your Prius? When does the sound happen, or what commonality would you say lends to the noise and rattle other than cold ambient temps? Are you moving driveway spots?

Best to let the Prius go through its warm up cycle before pressing the power button to turn it off.

 

Btw it does harm the engine

 

What exactly is happening?
What exactly do you think is being harmed?

 

i don't think what you're hearing is a problem. the one episode you had is best to be avoided in the future, if at all possible.

 

Continuous knocking will eventually blow a head gasket

 

Always let the ICE shut down before turning off the car. This should solve any further engine knocking.

 

Synthetic Oil (I recommend Mobil 1 0W-20) helps to some degree. As the oil is going to be less fluid during the cold starts, it's not getting to all parts of the engine as quickly. Synthetic oil is quicker to get to the entire engine.


I don't know much about that sound.

 

The one time I experienced knocking after start up was after cold-starting the previous day, and only running for a couple of seconds. This seems to be a cause-and-effect that a lot of owners experience.

If you experience knocking at start up, I would suggest to immediately turn it off, wait a few seconds, and restart. This dispelled the knock for me, the one time I experienced it.

And to (hopefully) avoid the situation, avoid the few-seconds-start-up-on-cold-engine.

 

So, regarding letting the engine complete it's cycle and turn off before turning the entire Prius off - is this just a 'common sense / sounds like a good idea', or do we know that this is best practice and why?

Thx,
- P

 

Experience.

 

As mentioned above: the one time I've experience this knock at start up is after running the engine cold, for just a couple of seconds. Starting up the next morning: got the knock.