Function of heat shield for rear muffler?

A part recently fell off our 2007 Prius. From parts diagrams, it is the rear mufller heat shield, part 58327-47010. Does anyone know if this part serves a critical function? I'm trying to decide whether to replace it. Our Prius recently joined the Priuschat 200K club, and we hope to make it to 300K. Thanks for your advice.

 

Kenny,

Thanks for your reply, but mine is a Gen 3, which has its 12-volt battery up front, under the hood.

Far as I know, there are only two options for what is above the rear muffler: 1) the gas tank or 2) the big battery for the hybrid system.

Neither would be good to overheat. So, I'll order a new part (around $80) and have the dealer replace it on my upcoming visit for its 205,000 maintenance.

Bill Nolting

 

Chapman,
Well, you are certainly right! I checked my Haynes Prius manual, and it does indeed show the 12 battery to be located in the trunk, on the right side of the vehicle. Even though I have jump-started my Prius twice long ago, I forgot that detail. And yes, you are correct that my 2007 is a Gen 2--I apologize for having posted this thread under the wrong gen.

Back to the point of my original inquiry, the 12V battery would indeed be located above the rear muffler! It's probably a good idea to replace the heat shield, in order not to overheat the 12V battery in hot weather. Other items in this area include the gas tank and the massive hybrid battery (which is under the back seat).

In any case, I have ordered the part and my Toyota dealer will install it tomorrow when I take her in for her 205,000 mile checkup.

Bill Nolting