Thanks for all the effort you have into this! It's certainly going to help me out since my car is experiencing the same symptoms.

Quote Originally Posted by Daox View Post
Without further ado, here are the test results...
Well...I think that pretty much confirms that there is apparently some issue/defect with the factory heater core. It's either corrosion or a restricted path through the core due to a manufacturing flaw. At least that's what I'm thinking. It's hard to believe it's corrosion when these cars are so new. Let us know how your follow-up testing goes.

This looks like an $800+ dealer repair...so people will want to test their own vent temperatures BEFORE their warranty runs out. For me that's going to happen by the end of this winter.


...thinking about the best way to open it up without getting metal shavings into the end tanks of the core.
Before you open it up, maybe flow some hot water through it to see if if you can observe any obvious temperature variations or cold spots.