Heater blowing "lukewarm" air

[chesterwellingt]

I just got a 1996 A4 Quattro, and with the heat set on HI, its blowing barely warm air. Even with the engine at operating temperature, its barely warm! Help!!!!

[morzechowski]

I just got a 1996 A4 Quattro, and with the heat set on HI, its blowing barely warm air. Even with the engine at operating temperature, its barely warm! Help!!!!

Heater core is dirty or bad. flush some lemon juice through it, then water, then blow it all out with an air compressor.

[AudiForeman]

Heater core is dirty or bad. flush some lemon juice through it, then water, then blow it all out with an air compressor.

or the thermostat is open or broken. same thing happened to my car a couple months ago. only 8 bucks.

[A4Rob]

Is your temp gauge reading between the C-H in the middle? If its not getting up to temperature, then you have a bad tstat. It is much easier to replace the Tstat than the heater core, so I would diagnose your problem first.

[hazard860]

wont hurt to flush your heater core either, just un plug the 2 hoses going in from the engine bay, hook up a hose to one end and flush water through, you'll see a bunch of crap flow out, then do it to the other hose so it flushes the system in reverse, do it a couple times and should help.

[esee135]

when mine went ice cold, I said screw it, pulled both hose sides off, put on some temporary flushing hoses and poured in CLR in the back flush direction, waited about 10 minutes, then started to flush it with HOT water, then I put compressed air on it limited to < 15psi, and it shot out some much garbage it looked like foam. A couple more rinses of hot water, and it was a champ. You'll find lots of rust and gunk and who knows what in there.

CLR may have been a bit on the aggressive side, but it wasn't working anyway, couldn't make it any worse. Mine got severely plugged because I had the oil/rad fluid gel up from the failed oil cooler and it took a while to clean and flush.

[BlackLock_A4]

There are so many threads on this topic. Let us know what you tried already, so we can help narrow it down.

Time to join the No Heat Club?

[Ldiaz12]

^^^ No heat? that must suck in the winter....

[Justin@FCP]

Check this link out, this might be exactly what you are looking for:

• if you're singing the "I ain't got no heat" blues

Is it a 2.8L? Purging the air out of the system can be a big pain in the 2.8L. I just got the heat partially back in my DD Passat after I had a Bentley tech partially drain the system, and vacuum fill the coolant back in. I now have heat, but not back to where it should be. Before it was vacuum filled, I attempted following the DIY steps on how to bleed the air out, and was unsuccessful. I'm just waiting until my friend has a chance to drain the system completely, and vacuum fill it completely. I'm really hoping that the key to getting my heat completely back is by having it vacuumed filled. I really do not want to replace my heater core!

[BlackLock_A4]

^^^ No heat? that must suck in the winter....

It does. I tried flushing the system w/ water, flushing it w/ CLR, changing Tstat, changed coolant temp sensor, and I bled the system after. I think I am just going to live with it. After I changed the Tstat, it started blowing a little warmer but still not hot like it should. I don't have a VAG either so I guess it could be the flaps not opening up to let all the heat in.

[Justin@FCP]

It does. I tried flushing the system w/ water, flushing it w/ CLR, changing Tstat, changed coolant temp sensor, and I bled the system after. I think I am just going to live with it. After I changed the Tstat, it started blowing a little warmer but still not hot like it should. I don't have a VAG either so I guess it could be the flaps not opening up to let all the heat in.

I believe it all boils down to how the system is filled, and if there is air in the system making sure it is fully purged.