2003 Passat V6 - Heater problem = cold air

[Ellie]

Happy New Year All. My 2003 Passat's heater puts out cold air. Not sure what d problem is, any idea/s? Thank you in advance.

[CotySinz]

Could be clogged heater core.

[scotts13]

Or, air in the cooling system, or a stuck mixer flap, a bad thermostat, or (if Climatronic) all sorts of servo or control problems. Tell us more about your car. GLX trim level?

[ashman78]

Hey scott, long time no see. We're experiencing the same in the wife's 01.5 GLX. I've known about the air in the system for a while, but I think it's finally plugged. I'm hoping the heater flush DIY works because I'm not looking forward to ANY of the other potential issues it could be -- bad heater core, bad Climatronic, etc

(VAG Com says Climatronic is working fine, so that's good)

[Ellie]

Could be clogged heater core.

In December 2011 VW dealership performed a flush to my heater core and said most likely the heater core is plugged up or partially plugged up, if it is not blowing warm/hot air. They said I will need to replace the heater core assy ( which is located under/behind the dash ) this is a big job to perform and the cost is somewhere around $1200.00 +/-

I just want 2b sure that's d problem n I don't 2 spend $1200.00 +/-

Any advise you guys can provide, would be great and TY.
Ellie

[JayTheSnork]

that would have been good info to provide in your original post to start this thread, Ellie.

after having recently replaced a heater core recently, I can verify that it is a time-consuming job. typical book time at a dealership will be about 8 hrs worth of work, or more.

[dbrick]

Flushing the heater core is lots simpler than removal and replacement, and some owners have been successful in getting enough junk out of the core that the heater works again. Search for "heater core flush" and you'll find the threads.

[Ellie]

Thank you. My 2003 Passat is GLX, 4 door sedan. Everything in my car functions well (175K mileage) b/c I do all of my service on time. The air conditioning works just fine. Thermostat is fine too. When I put the heater on 1st a lukewarm air comes out then quickly turns very cold. My service Mgr. at the dealership says I will need to replace the heater core assy ( which is located under/behind the dash ) this is a big job to perform and the cost is somewhere around $1200.00 +/-. I’m don’t to spend $1200.00 getting the heater fixed and hoping that’s something simple. Please let me know what other info., I can provide and thanks again.

[Ellie]

Yes, in December 2011, dealership the VW performed a flush to my heater core, but my service manager says most likely the heater core is plugged up or partially plugged up again and if it is not blowing warm/hot air I will need to replace the heater core assy ( which is located under/behind the dash ) this is a big job to perform and the cost is somewhere around $1200.00 +/-

[Ellie]

Sorry about that, here is my original post: My 2003 Passat's heater puts out cold air. Not sure what d problem is, any idea/s?

[CotySinz]

CLR flush with a drill pump if I remember correctly.

[JayTheSnork]

is there any gurgling in the dash?

I authored a thread in the Information Base forum titled something like, "If you're singing the I ain't got no heat blues..." - it is a DIY on how to flush the heater core, and also provides some additional info others have contributed to the subject.

[dbrick]

The service writer says the core must be replaced. This could be because he thinks it cannot be successfully flushed, or because the dealership would make more money on the larger replacement job. Some cores respond to flushing, but it's possible that the core is so clogged that flushing will not resurrect it. Flushing is much cheaper. If you can do it yourself, or find someone to do it, you may be able to solve the problem for considerably less than replacing the core.

[y2000passat]

An earlier post of mine explaining how I was able to clean out my heater core enough to get decent heat. I would definitely do this before spending $1200 to replace the heater core. Mine was putting out nearly zero heat before I did this. Cost is about $25 for the hose, pump, hose fitting and some coolant to replace what you flush out. Good luck with yours!

Disconnect the two heater hoses to the heater core - just to the driver side of the battery. It's 3/4" rubber hose. Get a length of 3/4" hose at an auto parts store. Cut it in half. Clamp a female end garden hose fitting to an end of one of the hoses. Fit them to the heater core hose connections. Connect a garden hose to the one with the fitting and flush. I took it a step further - bought a small submersible "fountain" pump used for circulating water through backyard water features at Harbor Freight for about $10 and connect it to one of the heater hoses. Put the pump in a container and circulate either CLR or a radiator flush through the core and return it to the container. You can do that for hours at a time. There's a warning on CLR to not use it on metals such as aluminum but I put some full strength on aluminum foil for hours and saw no effects. You can reverse the flush direction through the core. I now have heat - not a furnace, but plenty of heat.

[sf1991]

I have the same issue with my car even though I have had it flushed by two mechanics and no results. Now my mechanic says that I need to install a VW thermostat and not aftermarket which will good chance of fixing my heat? Does this make sense?

[scotts13]

Not really. If non-VW thermostats simply didn't work, they wouldn't sell them. Granted, given the trouble installing one, I personally would use OEM, but the fact it's "not VW" doesn't mean it's automatically suspect. (Unless you have the W8 engine)

[MR.CHIPPEDB5]

Well I have heat while I'm driving, it gets pretty hot, but when I'm in Park it's shoots cold air!! I'm stumped


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[Zodicus]

I am having a similar issue. On off or low my heat puts out nice warm air but any higher than that and it blows cool to welldigger's butt cold. I did have an incident the other day where many things under the left front and mid front of my car were ripped off (pesky canines) including the PS cooler and ambient temp sensor that just happens to be attached to the PS cooler. Since that sensor is gone I get no reading on my temp display on the MFD or on the climatronic for that matter. I am assuming that the sensor controls the interior temp? Will replacing the ambient temp sensor fix that issue? Thanks Passat World!