Hi all, got a 2009 hatch sti ppp and ive noticed the last few times driving it that there is a bubbling noise coming from the footwell when im stopped so im guessing its bubbles going through the heater matrix? The fans blow hot when temp is turned up on the ****, and cool when the **** is turned down. The coolant level in the expansion tank is spot on and hasnt moved at all since ive owned the car. It seems to be only noticeable when the engine is idling once up to temperature, but im not sure if it goes once im driving as i cant hear it due to road noise etc. The temp gauge on the dash sits where it always has done so im a bit stumped why im getting the noise! anything i should check or any advice is much appreciated, Steve.

 

Pretty common mate my old wrx used to do it as u say its the matrix!!!! Nothing to worry about!

Harri

 

yeah i just found it a bit odd as it only started doing it the other week! i wonder if theres a bit of air in the system? if so, could i start it from cold with the expansion tank cap off and squeeze all the rad pipes etc? or is that a stupid idea?

 

Yep sounds like a small waterfall behind your glovebox?

Start from cold with cap off and gently squeeze top rad hose to burp any bubbles and top up if necessary.

 

i shall give that a try, its not so much of a waterfall sound but like bubbles!