C5 Heater Core Issue?

[Wingc5]

Hi all,

reading about the heater core leaking and wondering if my C5 has this issue. The interior heats up fine, then when I go back to the car after it's been parked for a while post heater use, I'm often surprised with how much moisture is on the inside. I have seen a slight filmy type build up on some of the plastics when the car hasn't been used for quite a while, but I'd put this down to dampness due to slight water ingress. How can I tell for certain that the heater core is fine/is the problem?

Cheers.

 

[CaptainK]

Have you lost a noticeable amount of coolant ?

 

[Wingc5]

Not that I can say, but then again the car has barely been used in the last 12 months. Haven't noticed any leaks under the vehicle.

 

[teamzr1]

IF heater was leaking you would smell the crappy smell of anti-freeze inside the cabin area
But what most C5,C6 and C7 owners fail to do in their annual maintenance is there are 4 drains from the windshield
area that look like cow utters
This drains water and also A/C condensation down to the ground

Dirt, leaves, etc end up getting stick and closing up at the bottom of the utters as I show below

If allowing these to plug up then water can enter into cabin area or worse below the passenger hatch where electronics like the BCM are and do damage

For drivers side take front left wheel off and remove the small screws and pull clips and take out the small area of the inner fender off and as I show there are three of the utters there so clean all the crap out of them

For passenger side you have to take the battery out and reach in and pull that tube/utter out to clean and then install it back in

If you think there is water getting in on passenger side is taking the floor hatch off where the BCM, etc is and check for moisture
Depending on where you live maybe have to do this cleaning once a year





Passenger side with battery out



Crap plugging up the drain utters