Nasty Noises

[17swr]

I have a Jan 2010 registered T spirit, purchased as a an ex-demo with 2k miles on clock in May. Very satisfied after having an earlier T3 model. No probs to date but recently went on hols for a week leaving the Prius in my garage unused. When I started it for the first time after returning and the petrol engine eventually cut-in I got a horrible metallic clattering noise from the engine compartment! Not being to happy with that, I shut the system down while I mentally considered what to do next. Rightly or wrongly I restarted the engine and the unexpected noise had largely disappeared and did so completely within a few seconds. Thereafter it ran perfectly ok and has done so since. I use the car daily and the week long period of not being used was the first time since purchasing the car, apart from a 4 day period only a week after I purchased it in May when I had no such noise on restarting.

As a precaution I visited my Toyota dealership and told them about the occurrence asking for their advice. I was told that it was nothing to worry about rather it was due to the oil draining out of the engine parts during the period of standing idle, and that the noise was not unusual before the oil circulation was re-established. Unless there was a lot of smoke I need not worry!

I accepted the advice and left but am not convinced with their explanation. For me noise = friction = wear!

Has anyone else had this experience with their Prius?

[Jan&tone]

Welcometo the forum. No, I've had both gen2 and gen3 and never heard anything like you have described, even after a 4 week layoff from driving.

The oil in the gen3 is very thin though so I suppose their explanation could be correct. There are others on here with more knowledge than me though, so you will no doubt get other replies. Good luck

[Chris Dance]

I am no expert but I would ensure your dealer recorded your inquiry on your car records just in case it happens again or you get engine problems. I have not heard about this from any other Prius owners. The reason the dealer gave you sounds plausible.

[johalareewi]

Lots of posts about noisy engine starts on Prius gen3 over on PriusChat.

For example

http://priuschat.com/forums/gen-iii-2010-prius-care-maintenance-troubleshooting/81692-rough-engine-start-knocking-noise-startup-there-may-hope-yet.html

and

http://priuschat.com/forums/gen-iii-2010-prius-care-maintenance-troubleshooting/73163-engine-knocking-twice-startup-anyone-else-experience.html

You can even ask Grumpy Cabbie who has experienced this. The concensus seems to be it can happen randomly and is nothing to worry about. If it does it all the time though...

[17swr]

Thanks to Johalareewi for your reply, (also to Jan&tone and Chris Dance for their replies). I took a look at the links you suggested - still finding my way around this forum, but its great!

I take comfort in the reports from others and can see a pattern which could explain what is happening with my Prius. Most of the occasions I jockey the car on the driveway, I switch to EV simply to prevent the petrol engine running for a short time which I know does the exhaust system no good at all. Sounds like its even more necessary, to prevent this engine rattle! The time in May when I left the car for 4 days was immediately after a cross UK drive so the engine and its components would have been good and hot and evaporated any unused fuel - so then I had no rattle. So sounds like short bursts with the engine cold should be avoided as far as possible. Glad there is a 5 yr warranty on the important bits!!

[Grumpy Cabbie]

It is a common but rare problem. It happened to me once back in January and there are many reports of this problem on the US Prius site. It seems to occur after the car has been stood for a few days, often in cold weather. There is no fix as such as yet as it is very rare and almost impossible to replicate, though some believe it could be caused starting the car but then shutting the car off before it has finished its first warm up cycle and then leaving it for a few days.

If you are unlucky enough to have it occur again, just switch off, leave for a second of two and then restart. If it persists then certainly get it checked out as it could be something else such as a dodgy coil pack.

[17swr]

Thanks Grumpy Cabbie. Your comments fit in with several others so it gives me some things to look out for when and if it occurs again.

What a great forum! Lots of helpful comments in such a short time. As a new member I'll definitely use it again - although not because of problems I hope!!

[kevin h]

Thanks Grumpy Cabbie. Your comments fit in with several others so it gives me some things to look out for when and if it occurs again.

What a great forum! Lots of helpful comments in such a short time. As a new member I'll definitely use it again - although not because of problems I hope!!

Its the engine missfiring.

My dealer was able to duplicate it.

To try identify why it happened they drained my fuel tank and asked me to monitor the problem if it re occurred.

so far so good (Its been nearly 6 months) and its not happened again, but they did think it was down to either bad fuel or running the tank to low and so picking up some muck from the bottom of the tank.

All details were reported to Toyota UK, but no definative reason has been provided.