Having problems with your 2003 Volkswagen Passat ?
Hi. Actually I have VW Passat 2003 which recently stopped blowing hot air through the vents. The fan is still working but no hot air. A friend tells me that the unit that regulates the flow of hot water is faulty. If he is correct, what is this unit called? Many thanks.
Scale builds up in the bottom of the heater core. When it gets high enough, it chokes the flow of hot fluid and the fan can only supply cool air. When mine was doing that I disconnected the in and out hoses at the fire wall and flushed it out with garden hose pressure. A lot of junk came out. I reconnected the hoses and bled the air out. It worked good immediately. Two weeks later it happened again. I did repeated the procedure with equal results. It happened again every several weeks for about five or six times, each time lasting a little longer than the last. I guess I need to flush the whole engine out to get all the junk out instead of just the heater core. BTW, the stuff that comes out looks similar to sand if you capture it in a bucket. It sinks to the bottom of the water so you can see it. It must be sinking to the bottom of the heater core, too, and that's why it chokes the flow off.
Repair Help & Product Troubleshooting for 2003 Volkswagen Passat
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