Mine was clogged in my '02 Audi A4 and instead of doing what you did, I put two hoses on the intake and exhaust of the core, poured CLR down that bitch until it came out the other hose, let it sit for an hour, then rigged up my hose to the intake and blasted all of that CLR and calcium buildup out of there. Had to do it twice, but man having heat again after no heat during a brutal MN winter was a godsend.
Pros: having heat again
Cons: core was clogged
Vehicle:
Audi A4
