[DomonationsMZ3]

Anyone check their engine bay and see that the black plastic intake runners have a foam piece stuffed under the plenum/chamber?

I pulled this foam piece out so I could access my pcv valve which is not possible without removing the whole intake plenum.

There is also another foam piece attached to the inner side of of the plenum too (adjacent to the cylinder head). Would anyone know what these foam pieces are for? I do not notice any increase in sound while driving without it, nor are these pieces indicated on the Mazda3 shop manual for the intake removal.

--Is this for sound/vibration insulation or for heat insulation?

--Is this a US market application only?

 

[shay2nak]

If I had to guess, most likely it's for sound suppression.

 

[rjt1]

Not US market only ... I have that foam on my 2.5l Mazda3 in Australia.

 

[DomonationsMZ3]

Not US market only ... I have that foam on my 2.5l Mazda3 in Australia.

Neat, I wondered if this was a US only spec application. Any insights as to what it is for?

Sound suppression for sure but more specifically, you think its for heat suppression too? Or reduction in engine vibrations that may potentially crack the plastic intake runners?

I'm gonna put mine back on since I finished messing with my PCV system and worked on installing a oil catch can on it.