2015 Passat TDI heater core fixed, still no heat

hotrod624

New member
Joined
Oct 23, 2020
Location
Oklahoma
TDI
2015 Passat TDI
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

Veteran Member
Joined
Jun 7, 2017
Location
Twilight Zone, WA State
TDI
2005 Passat sedan - SOLD; 2013 Passat DSG; both purchased new
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

New member
Joined
Oct 23, 2020
Location
Oklahoma
TDI
2015 Passat TDI
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.
 

akerly

New member
Joined
Oct 31, 2020
Location
Croatia
TDI
1.6
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

Veteran Member
Joined
Aug 6, 2009
Location
North Haven, CT and Brooklyn, NY
TDI
2012 Passat Gasser VR6; (Sold and missed) 09 JSW DSG Pano Blue Graphite Build Date 05/09
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.
 
Top