I have a 2004 cayenne turbo, I have previously replaced the infamous coolant tubes, and the tee fitting, along with the other hoses on the back of the engine. Now, it appears to have a new leak that is coming from a rubber/plastic protrusion in the firewall on the passenger side (directly above the exhaust) This appears to be a vent or drain but I am unsure. Once the system builds pressure a stead drip develops from this part. Anybody else seen this? Bad heater core?

Thanks,

Doug

 

Okay, to update. The "protrusion" in the firewall is the drain for the AC/Heater box. The coolant must be coming from inside and draining out of the rubber drain. The question now is does anyone know of a tutorial/DIY to change the heater cores? (assuming it is the heater cores or one of the lines inside the HVAC box)

 

Mine did that when the coolant reservoir cracked where the top/bottom piece is glued/molded together. $75 later it is all fixed.

 

If the heater core is leaking, you should be able to smell it in the cabin with the fan on.

 

I thought the same thing but I don't really smell anything. Looking at the coolant it appears pretty diluted. It definitely is coming from the drain tube in the firewall. I pulled the passenger side lower dash panel and removed the rubber drain and it was still coming out from where the drain attached to the HVAC box. I am assuming it has to be something inside there leaking (heater core/hose/connection) It doesn't leak until it gets full system pressure, actually, it leaks the worst a few minutes after the car has been driven and then shut off. Anyone have tips for getting access to the heater cores?