LOUD Banging/Rattling at Start Up!!!

[Blind Guy]

This morning when we went to start the car, it started normally, going into NO ICE initially, then after a few seconds the ICE came on and immediately there began a LOUD Banging/Rattling sound from the engine compartment. It was VERY, VERY loud! It was NOT a metalic sound, it sounded more like plastic, but not the plastic piece that covers the head of the ICE, it sounded more substantial than that.

We immediately stopped the car, my wife looked under the car and under the hood for anything loose or disconnected, but there was nothing obvious.

She started the car again, and everything worked correctly, and for the rest of the day.

Any diagnosis.

David (aka Blind Guy)

[atroader]

I couldn't ignore this one. I speculate that some road trash might have blown up under the car towards the end of the last commute, or a rodent or something may have found a place to rest. The 2010s do not have an accessory belt right?, but this could have been located near one of the cooling fans.--

Was the A/C on when the car was started?

[Tideland Prius]

Parking brake?? did it rain recently?

[Bobsprius]

Sure sound odd, but as one poster mentioned could something have gotten in the cooling fan area perhaps??? You have not had it in for service in the past day or 2 prior?

Sounds like something was in the fan blade area, but maybe a check of that area to see that all blades are intact etc and nothing is stuck inside..PEST, BIRD..etc..

[a64pilot]

Completely baffled as I can see nothing that moves when the ICE runs except a bare pulley, AC and fans are independent of the ICE aren't they?
What would water do?
Was the car moving when it did this?

[jburns]

Here kitty, kitty, kitty.

[Blind Guy]

THANKS all for venturing a diagnosis, there were no critter strikes or debris intakes during the previous drive, the car is kept in a closed garage, the fan blades were checked and the sound it made was NOT that of an animal or debris of any sort, the sound was of something SOLID and NOT metalic, more a solid plastic of some sort, but again, it was VERY, VERY LOUD!!!
* (I'm NOT saying it was plastic, because I do NOT know what it was, I'm reasonably sure I know what it wasn't).

Used the car again tonight, and everything worked as advertised!

David (aka Blind Guy)

[qbee42]

Are there any other blind guys in your neighborhood? Are they all accounted for?

Tom

[robrian7]

You wrote, "This morning when we went to start the car, it started normally, going into NO ICE initially, then after a few seconds the ICE came on and immediately there began a LOUD Banging/Rattling sound from the engine compartment. It was VERY, VERY loud! It was NOT a metalic sound, it sounded more like plastic, but not the plastic piece that covers the head of the ICE, it sounded more substantial than that."

This is NOT what you think it is. This has happened to me twice. What you are hearing is the engine trying to "catch" as it transitions from all-electric to ICE (internal combustion engine). I brought this to the attention of my local dealer and they said this is the first they have heard of it. It sounds like it may actually be an issue w/the engine(s). The sputtering/shuddering you're hearing is LOUD and I wondered if I ruined the engine or not, but just like in your case it did not occur after that. The best thing you can do is to make a note of it and report suspicious activity such as this to your local dealer. They should be keeping track of these issues. If nothing else, it begins a paper trail in case other issues arise in the future.

Other 2010 Prius owners may have had a similar experience. This is a good place for us to share our experiences to get the word out.

[spiderman]

Originally Posted by robrian7

This is NOT what you think it is. This has happened to me twice. What you are hearing is the engine trying to "catch" as it transitions from all-electric to ICE (internal combustion engine).

Hmm, perhaps the intake/exhaust valves where open and it had a little pre-ignition into the exhaust manifold? Just a guess.