Engine Knocking/Shaking During Startup on 2012 Prius

I've had this happen twice now on my 2012 Prius; once shortly after 5k miles and again now after about 7k miles.

Both times the car had been parked in my garage overnight, and both times the previous day I had moved it around the driveway for short durations, not allowing the engine to fully warm up immediately before parking it. Temperatures in both cases were low; first time around 15 fahrenheit, and the other time around 30 fahrenheit.

I have not had a check engine light or code thrown, but it sure feels like something in the passenger side of the engine compartment is about to vibrate itself right out of the engine bay! I was going to mention this to the dealer when I had my 10k service done, but now I'm thinking I should mention it sooner.

Definitely not a problem I would expect with a car less than 5 months old!

 

Just "Hang/On" & smile.......

 

I just picked up the car from the Toyota dealer today. Was told that this is not a common problem, although there is a technical bulletin for this issue.

Does technical bulletin mean it's covered under warranty?

 

Typically, but a TSB can also apply to vehicles out of warranty... it all depends on what it specifies.

 

I've never see that in Toyota. TBS are always limited to the warranty coverage. You probably meant service campaign aka recall.

 

Add me to the 2012 engine startup noise list. Bought the car new in March of 2012. Happened a few times in June July timeframe - all three times in WARM weather, and in the morning. No car washes before and no short distance motoring. We live in the sticks so the car always warms up fully by the time it gets home and is parked. Never threw a code and hasn't happened since (she's hitting 30,000 mile today). I will keep an eye on this thread going forward.

 

Just had my 2013 do this today. I cut the car off right away & restarted. It was fine then. It was 80 today. Hoping it is just bad gas. I have 21K miles on the car. First time it has happened. May put in some fuel treatment just in case.

 

I'm purchasing a 2012 Prius 2 from my organization's fleet. It has 82,000 miles on it. I haven't purchased it yet, but I have driven it about 1500 miles. This morning I experienced the "shake." Are there any updates, or is this thread dead? I was wondering how much it costs to get this issue fixed (if the IM actually fixes it). I have the opportunity of purchasing a warranty and thought if this was an expensive repair, I'd be proactive and pay for the warranty in case I needed to get this fixed at some point. Thanks for all the great information.

 

there's no fix, but it's not a major issue. try not to shut the car off while the engine is running.

 

What's "IM"?

 

Intake Manifold.

 

I own a 2012, but I haven't had any knocking issues yet. I try to use EV mode for short distances. I drive it at least once a week on the highway for two hours to burn off any contaminants. Hopefully, I won't run into this problem.

I live in Canada and I use mostly costco gas. I'm not sure if our gas has better detergents.

 

fingers crossed!

 

Both my 11 and 12 have done that but not in a very long time. It may be cold related?????

 

Mine hasn't either since the new intake. Chances of condensation is greater when temperature differences (ambient and engine) are the largest, so yeah, it makes sense that the know would occur more when cooler. Even more so when the humidity is higher.

 

BTW/retiring 8 Jan for the 4th time will be able to view this forum at home/LOL

Still think this is a fuel too lean issue on start up.

 

The reason behind the knock works like this: you had started the car the 1st time and moved it to the grass, wash it , then started it to move to another area ( then the knock started) : This is: the oil pressure has released the VVT locking pin after you started it the 1st time and moved the car. then stopped . The VVT lock pin didn't re-engage . and the oil pressure doped away the VVT camshaft is then free and the chain tension has relaxed. The second start of the engine has to turn a short time to create oil pressure to drive the chain tension piston out and the VVT camshaft locking pin back in place. BUT in that time the camshaft is moving "advanced /Retard and the chain is flopping around All this would take around 5- to 10 second . then the issue is gone .

 

And......this is ALL happening without any added damage/accelerated wear etc. ......

 

Anybody with an answer yet on the reason for the cold start knock?

 

Yes, it is in the oil catch can thread.