2013 Prius scary noise at Cold start.

Our Prius will knock at start up sometimes, particularly if the engine hasn't had an opportunity to warm up once it starts. The next time it starts is when it will knock. But yours sounds much louder.

 

you are not alone. this is a known issue by toyota, of which a TSB was issued, of which the TSB did not correct.
My guess is before this occurs you move the car a short distance, out of a garage, or out to the road without the car being able to completely warm up. Once this happens in colder weather the knocking will occur on the next start up.
Read here for more info
NEW!!! Service Bulletin for Engine Knocking at Startup T-SB 0012-10 | PriusChat

 

same here, surprised you bought another piece of junk toyota.

 

while concerning its an issue Toyota knows about, can recreate and impacts nearly every Prius. So i'm going to go ahead and place my faith in Toyota engineers that its a non issue in the long term engine health of the car.

 

mine and my moms prius also do this in the winter. My moms only got like 40 000 miles on it, mine got closer to 200 000 (its been a taxi). And mine is still alive, so i dont think its anything thats unnormal or dangerous

 

Mine has made that ugly noise twice now when starting on a cooler morming....and now to think about it, both times were after I had previously moved the card from one parking spot to another. Hmmmmm. Note to self, don't turn off car until the ICE shuts itself off.

 

exactly.

 

This was precisely the case. I moved it yesterday and today it made the knock. 118K miles on the car and never ever heard it before today. Thank you eliteconcept

 

Have a 2012 Toyota Prius v. Just went to turn it on and it made a loud 'scary' noise. Mechanic doesn't open for twenty minutes, and he's 250 miles away. I did not move the car in electric mode before parking it yesterday evening. Perhaps unwisely, I immediately turned the car off - like within seconds. I will turn it on again when the mechanic asks me to when I call in.

For the record, I think I searched for 'loud thumping noise when turning on Prius' but I immediately clicked into this thread. I don't believe the car had that TSB done - I bought it used but have the entire dealer service history. 77k miles now (bought it two months ago at 70k) and this is the first time it's done something I don't like. Fwiw, it's 57f outside.

 

Does it sound like this?

This was mine with a dead cylinder

 

It did indeed sound a lot like that, but fortunately it went away after perhaps ten seconds. Then I remembered that I'd gone outside to make a phone call the night before, and sat in the car (with it running) for about twenty minutes. I knew I hadn't moved it, but running it to sit in had slipped my mind.

I will have to see if my car is eligible for the TSB service that doesn't really work =p

 

running it for 20 minutes wouldn't cause it. running it for 20 seconds might.

 

My 2012 has a quick grinding sound when starting. Happens in mostly cooler weather with dampness possibly playing a role too. It's random and doesn't happen on every start but it's been doing it since brand new.

 

I don't know if I've experienced the grinding sound. This was LOUD, thumpy, and honestly scary isn't an unreasonable term for it. I'm crazy grateful it's 'normal' and hopefully easily avoided.

 

I'm trying to remember if I perhaps had some reason to briefly turn it back on after the phone call. Nothing comes to mind but it's possible I did it on autopilot and just didn't log it to memory.

 

what can cause detonation (the sound you're hearing) is incomplete combustion. this can happen when you turn the car off during the warm up cycle. unburned hydrocarbons sit in the intake manifold and the next time you turn it on, bang, bang, bang.

the other issue may be a clogged egr