2015 Passat TDI EA189? Coolant hose issues


Sep 6, 2022
Chesapeake VA
2015 Passat TDI SEL
Heater Core. Since 9/3/22 I’ve blown 3 of these fittings. I didn’t know there was no heat til the night before the last break on 10/23. The dealer fixed the 3rd one under warranty of his fix 2 weeks prior. I asked them to diagnose the heater core and the duct sys valves. They said the heater core is blocked cuz the louver things showed ok on their test. But they wouldn’t say the heater core blockage would cause the part to blow. They wanted $1200 for the heater core job. I had to say no thank you. I got a $70 Nissens 561819031C heater core cuz I read on a forum they had larger passages. It took 2+ hrs to replace following this Youtube video. I cut open the bottom end of the heater core to find 3/8in clumps of black clay. 3 dealer flushes had no effect on the heater core blockage. After I got it out and before I cut it open I blew hard in the lower hole to see what the resistance was. There was some but I displaced the clumps I guess. I’m a blowhard. I can’t figure how to paste pics from a iPhone. If there’s a blockage at the heater core would more heat build up at the fitting and blow it or is there more pressure at the fitting bc of the blockage? I hope this helps somebody.


New member
Sep 20, 2022
Santa Ana, CA USA
2015 Passat TDI SE. (US model)
I have posts in another thread on this issue (and others have similar issues), but even with complaining to VW this is what I got covered and not covered on my 2015 TDI Passat - (In service date in Feb 2018 so post scandal but out of base warranty):

July 2022 - Water pump - Covered under TDI. - 61K miles - South Coast VW - Santa Ana, CA
Aug 2022 - Heater hose - Not covered - About 66K miles -VW Topeka
Aug 2022 - Heater core block - Not covered - About 66K miles - Emich VW Denver
Aug 2022 -Aux coolant pump - Not covered - About 66K miles - Emich VW Denver
Sept 2022 - Heater core - Covered under TDI warranty - About 67K mile - South Coast VW -Santa Ana, CA
Oct 2022 - Ground to Aux coolant pump not good (additional ground wire added) - Covered under TDI warranty - About 68K miles - South Coast VW, Santa Ana, CA

My out of pocket on the above non covered repairs was about $4,000.

Complaints were made to VW customer relations who worked with the dealer service manager in Denver. Dealer in Denver did not think that his uncovered repairs were warranty (even with the subsequent repairs) and would not unwind and re-submit as warranty. Denver had wanted to change my duct valves, but I didn't what changed (and the valves are functioning properly now - There was just no heat because of the partially blocked heater core).

Once this car goes beyond the TDI warranty I would replace with the heater core with the Nissan part, but because it was covered I stayed with the VW part.

2015 TDI is very tough on the VW coolant with the changes made in 2015 to warm up the engine faster. I think the VW changes that were done for the fix put even more pressure on the cooling system (for the 2015 cars).

This car was great from Feb 2018 to July 2022 but has been a nightmare since. It's probably had about 30 shop days in 3 months! This car will probably be up for sale in the next year or so, and certainly no more long trips with this car.

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Veteran Member
May 17, 2010
Central FL
2011 JSW DSG (buyback, RIP), 2014 JSW TDI, 2015 Passat TDI, 2013 Jetta TDI.

Erosion from Diesel Gate Grit. Solids forming in the coolant from excessive EGR temperatures. Flush your systems. Be ready to change more plastic parts in your system. It is emissions related, and covered if warranty is still in place.
holy NASTY! thank you for sharing!


Aug 27, 2021
St. Louis
2015 Jetta SE
This was my problem last winter for 2 months. Broke that plastic piece 3 times - all replaced by dealer under warranty. They tried replacing the EGR cooler as a fix, until I found a thread on heater core causing this issue. I replaced the heater core while it was broke, got it in to the dealer for them to replace their fitting that broke again. Only, they told me the heater core was covered under the Diesel gate extended warranty. So lessons learned is to attempt to get the heater core replacement done under warranty since it is apart of the coolant system before doing it yourself and ultimately "voiding" warranty.