2015 Passat TDI heater core fixed, still no heat

[hotrod624]

Hey guys, new to this forum . Me and the wife picked up a 2015 Passat TDI a couple years ago, we started having trouble with the heater core and got it fixed. Heat worked good for about two weeks, now the heat has vanished again! Any other area's where I should be poking around? I've always done my own work but the extended warranty covered the heater core fix, can't complain about lol. Anyways I appreciate it.

 

[Tom in PT]

In these cars some heat problems are caused by blend door motors failing. Is your drivers side getting heat, no heat on passenger side, or some other situation?

 

[hotrod624]

I don't have dual climate control so it's cold no matter what you put it on. I had it scanned and its not throwing any codes. I'm taking it back Monday and they are going to look at the heater core again.

 

[BRIAN427COBRA]

Fix the blend door

 

[akerly]

We had this issue with our Variant, they turned everything inside out until they found out one of the hoses which has non-return valve got clogged. Exchanged the hose and heating works no problem now

 

[MostroDiesel]

I'm currently trying to figure out a similar issue in my 2012 VR6 (not diesel). I replaced the heater core a year ago, and it continued to produce tepid heat on the passenger side -- good on the driver's side.

I believe all blend doors are working, electrical stuff is up to snuff, and so believe the core is simply already clogged again. I plan to try backflushing it soon, as it seems to be worse than last year now that the cold weather has returned. Does anyone know which hose is the feed and which is the return? I want to flow the flush water BACKWARDS. I'm interested in the non-return valve too...that would be interesting to know more about. Although the gasser vs. diesel systems may be different.

Any ideas from the peanut gallery? And, if I figure something out, I'll be sure to post my results.

 

[hotrod624]

Drum roll please!!.... It was the blend door. Got it fixed and haven't had a cool day yet!

 

[Smashed Ixnay]

I hope it stays fixed. The dealer diagnosed no no heat issue as the heater core, so I spent $1k to replace it. Every time I drove off the lot the heat wouldn't work after a couple of miles. I was also losing coolant at a rapid pace. Took me over 3 months for them to finally fix the issue, which was the EGR Cooler that supposedly had an "internal coolant leak" and sending trash through the lines, almost clogging up the heater core immediately. Every week for 7 weeks I would drop it off, they'd vacuum the lines, then say it's fixed. The EGR Cooler, DPF, heater core again (on their dime this time), and a bunch of sensors were changed to fix my issue.

 

[hotrod624]

Whoof, that sounded like a hassle! Glad you got it figured out.