VW B7: Coolant Flush / Heater Core Flush

roycheck99

Member
Joined
Oct 16, 2019
Location
CT, USA
TDI
Passat TDI SE '13
Hi all, I'm pretty handy and can do basic car work but by no means am I comfortable working on cars. Its a known issue that the heater cores have a serious design flaw with the VW B7's. I've had my heater core replaced 3 times by VW while I was still under the extended warranty but I lost most my heat last winter. I'm trying to figure this out before the harsh New England winter hits.

Currently my car outputs 135F from the left vents, 110F from the Left Center, 100F from the Right Center and 90F from the Right side vents. My wife will no get in my car during the winter since its blowing cold air on her.

I called VW and was quoted about $800-$1000 to replace the heater core and to do a full system flush so I decided to take this repair on. I've been doing so digging and can't find good instructions how to properly flush the coolant system to full empty out all of the coolant from a 2013 Passat TDI.

First, I've pulled the lower radiator hose off and captured only about 1/3 of a gallon of coolant from the system. Most of it seems to be from the radiator and from the coolant reservoir. Obviously this wasn't close to the amount of coolant I expected so I filled up the reservoir with distilled water, ran it until it got up to temp and repeated to drain through the lower radiator hose. After 5 cycles, I was still getting a good concentration of coolant but had to stop for the moment.

I put some Prestone Radiator Flush and Cleaner into the system and been driving on it for the past few days. I'm now looking to drain the system again to get all the distilled water and the cleaning agent before pulling the heater core hoses and refilling with coolant.

My question, does anyone have a good procedure with pictures or video how to fully drain the coolant system for a 2013 Passat TDI. And does anyone have a good procedure (pictures/video) and tips about flushing the heater core for a 2013 Passat TDI?

Thanks in advance for the help fellow TDI drivers.
 

rustycat

Veteran Member
Joined
Dec 27, 2012
Location
seattle
TDI
2015 passat sel
There was a great instruction here on using a shop vac to drain the system. Hopefully, someone bookmarked it.
 

roycheck99

Member
Joined
Oct 16, 2019
Location
CT, USA
TDI
Passat TDI SE '13
I was able to find the coolant flush procedure using the shop vac. Worked way better than pulling the lower radiator hose. After flushing the system a few times and connecting a garden hose to the heater core inlet and outlet in attempt to unclog, I'm still getting poor heat on the passenger side.

Has anyone had good luck unclogging a heater core? I have 150k mile so I'm outside the warranty
 
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