Loud, Rough Cold-Start= Exhaust Manifold Replacement. Why?

The bulletin they are speaking of involves replacing the intake manifold (not exhaust manifold as they may have told you). What does seem interesting is that the revised manifold discussed in T-SB-0010-12 was used as a running change to the MY 2011 vehicles. Not sure why your 2012 would benefit from another of the same manifold.

Let us know how it goes.

Jeff

 

Is this covered even after the warranty expires since there is a TSB?

 

It is only covered under the Powertrain warranty (60 mo. / 60k miles) OR it will be covered under the CA Emission warranty in certain states until 180 mo. / 150k miles.

 

I am having the same issue with my 2012 Prius, it seems like if you start it and move it quickly and shut it back off before it warms up, the next time you start it, sounds like the engine is knocking, rattling, about to fall out. I am going to take my car in to the dealership as well. Mtbjay, I just don't understand, there should be no water in the intake manifold or in the EGR passages, who gave you that information ? Any water inside the motor will damage it unless it is flowing in the cooling system.

 

Sounds like you either got an older intake or the new design didn't cure the issue. Solution is to never let the ICE start up and you shut it down before it goes thru it's warm up cycle, which is only a minute or two.

Mike

 

I had the TSB for the manifold done on my 2011 Prius a while back. Just last month had the knocking noise come back. Although before the knocking would last 15 to 21 seconds, it now only goes for a very short 3 seconds.

 

So mostly cured

Mike

 

I've noticed that the 2 or 3 times it has happened to me was when I was trying to move my car from my driveway to the curb in front of my house (after washing the car). If the engine just fired up (< 3 - 5 seconds) and I shut it down, I would get the knocking event. Now, I just let it run for 15 seconds or so to avoid it.

Dumb.

 

Mine seems to always happen when I wash it also. Water / moisture is getting in somewhere and causing the knocking.

 

Maybe she's not happy 'cause you got her wet

Mike

 

Interesting… I experienced this same type of issue with my 2012 last weekend when I was installing my carbon fiber dash.
I had the doors open for a long time (i.e. interior lights on) when I noticed the lights start to dim. I started the car to allow the alternator to charge the battery. I don't recall exactly but i just remember starting the car and hearing a loud “tapping like” noise coming from the engine compartment. The car shook too. It only lasted a few seconds and has not happened since. My Prius is only a month or so old

I didn't associate it with the quick start up/shutdown... although I may have started the car and turned it off fast because the garage door was closed. Then opened the garage door and started it again, and that is when I heard/felt the noise.

Should I be worried about this?

 

It appears all of our cars will do this. Toyota might want to design a new intake or just give all of us a extended warranty to cover the gas motor (ICE) if it should fail later on. Now that we have identified how this issue happens, owners can eliminate the issue by letting the computer run the motor through it's warm up cycle before powering the car down.

Mike

 

My 2010 Prius just had this problem yesterday (bought it late 2009). It occurred when I moved the car from the driveway to the street. My wife started it up the next morning and it ran rough at start-up again. We took it in to Toyota and they are replacing the intake manifold.

I just don't understand why we never experienced this before but we have now. What changed? Why now? I have moved it from the driveway to the street before without issues.

It seems like the car engine turned on even though I was under 10mph moving it from the driveway to the street. I wonder if putting the car in EV mode would have kept the problem from occurring.

 

I'm assuming that this time the engine fired up and ran for just a few seconds, whereas before maybe it didn't fire up at all or if it did fire up, it ran longer (10 seconds or more).

It won't go into EV if the engine is too cold, even if you keep the mph below 10 mph (you'll get a warning message if you press the EV button when the engine is too cold).

If you have the opportunity (but I doubt you will get it) it would be great to have the tech power up the car (cold engine) until the engine runs and shut it down after 2 seconds. Then restart to see if you still get the knock (the advantage of having the tech do it is that is it already at the dealership and they can't say you imagined it.

But, likely, you'll get your car and the engine will already be running and warming up (past the stage where you could shut it down and get a repeatable knock). The only other alternative would be to leave it there a few hours or overnight, and do the quick power up and shutdown on a cold engine.

 

PLEASE.....I need to see the video your wife found online. My dealership is trying to get my Prius to rattle again before they dive into this major repair.

 

Here's one:

Just search You Tube for Prius Knocking.

Mike