I have a 2003 Passat that has been a great car. Fortunately, I live in Texas, because the heater hasn’t worked for 2 years now. I get by wearing a coat on the rare “really cold” days we get, and I have blanket in the back for the kiddo. Unfortunately, the lack of heat has also made my defroster far less effective. I have a friend who was a VW service advisor tell me that the heater core probably needs to be flushed as a first attempt, but when he remembered that I have the V6, he wasn’t sure if there was room to access what I need to in order to do the flush. I have some mechanical ability, but no one will ever mistake me for a mechanic. Does anyone here have experience with doing this job on this car or something similar enough to be able to give me helpful pointers about how to go about it? This is my only car, so I cannot afford to be without out it.
The inlet and outlet pipes on the core tank may be inaccessible, but the hoses leading to them should not be. Flush it through the hoses. Be aware that there may be a valve in the inlet hose that will need to be energized to allow flow of the coolant (or flushing water…I recommend a garden hose).
The valve can be readily energized by turning the ignition switch to ON and the heater to ON. Do not run the engine to energize the switch, as you do not want the engine running with an open cooling system…and besides, you’ll make a mess.
Here’s a video of one guy’s solution to flush the 2003 Passat V6 heater core. https://youtube.com/watch?v=B_kI5jmoquI You should be able to get to the heater core hoses without shifting the engine at all. Apparently, plugged heater cores on Passats are fairly common.
Is your temp gage showing normal? If it is showing below normal after your car has been running a while, you may need a new thermostat. I live in Minnesota and had low heat (and temp gage showing low) and after replacing the thermostat, it fixed it. Much easier fix than a flush.
At our shop we usually find that the Heater Core is plugged