2012 (MK6) Jetta TDI (2.0L CR) - interior (cabin) heating sucks & future upgrade

Just finished installing all my upgrades and parts to my jetta. Up here we have been getting some really cold weather. My interior heaters do not seem to be blowing anything but Luke warm air. I noticed this after I installed the frost heater (possibly air in the lines). Also we did not use G12 when topping up the fluid level. Any thoughts?

Also, I am stuck on what to upgrade next. Any thoughts? I was thinking S3 intercooler.

You need to bleed the system to get the air out. I would drain all the coolant and replace with G12+.

If you didn't use G12 / G12+ to top off, you might have just screwed your whole cooling system. There are members here that will walk away from a deal if there's anything 'green' in the coolant reservoir. What kind of coolant did you use?

I installed a FrostHeater last winter, and have had zero issues since. Didn't even lose enough coolant to warrant topping it off.

Ya I am fairly sure I will have to flush the coolant system.

The A4s were self bleeding, and I don't think A6s have a bleeding valve either. When it's super cold the thermostat takes a while to open.

All I know is it was generic "deisel" coolant my cousin had kicking around. I am getting the system flushed tomorrow.

I thought all A6 Jetta's in Canada came with coolant heaters as standard?

I just had my coolant system flushed. Turned out to be air in the system.

That's great news! Hopefully no more green stuff in there this time.

Agreed! Anyone have some suggestion of what I should upgrade next?

Don't want to touch the nozzles yet. I was thinking S3 intercooler and coil overs.

Currently:

MagnumFORCE Stage-2 Si PRO 5R Intake Systems
Snow Performance MPG-MAX™ VW TDi
Tubodischarge TDI Turbo Discharge Damper
MACH Force XP 2.5" Cat-Back Exhaust System
Rawtek 3" down/mid pipe with DPF/EGR delete
Malone stage 2 ECM and DSG tune
LED headlight assembly
Zenteck HID 6000 high beam, low beam, and fog lights
smokes headlights and taillights
5% tint on the back 5 windows
50% tint on the passenger and drivers side windows
Black "VW" Emblems