Audi A4 avant (b5) 1.9tdi no heat from heater

Tiny
GARYVEEVERS
  • MEMBER
  • 1998 AUDI A4
  • 177,000 MILES
Help i've bought a car with no heating, seller says he bought it also with no heater so have no history on how it went or why. Its an audi a4 avant 1.9tdi estate 1998 (b5). A/c pump has gone but also have no heater, blows out cold air. Have bled the system for ages getting the air out, temp goes steadily to 90 most of time but occasionally drops suddenly. Top hose from radiator goes red hot all the time but bottom hose isnt as hot.I know the a/c pump has gone but i've checked thermostat; brand new, changed head gasket, timing belt, still nothing. Vag-com results say too many errors (excessive comm errors) on channel 08; auto hvac. Altered density etc, but cannot get any fault codes for this code number however I try. Only found errors on channel 35; centr. Locks.16 in total, 7 of these were unknown error codes.
any ideas?
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Friday, January 27th, 2012 AT 9:34 PM

7 Replies

Tiny
JACOBANDNICKOLAS
  • EXPERT
With the engine running, hot, and the heat on high, feel both heater core hoses. Both should be hot. If only one is hot, try flushing the heater core. If both are hot, check the blend air door for operation.
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Friday, January 27th, 2012 AT 9:36 PM
Tiny
GARYVEEVERS
  • MEMBER
Both are hot, where is the blend air door? We've found loads of flaps and all seem in good condition
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Tuesday, January 31st, 2012 AT 3:36 PM
Tiny
RIVERMIKERAT
  • MEMBER
Slowly move the temperature control back and forth with the engine running and heater on. Watch for actuators and levers moving on the airbox under the dash.
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Friday, February 3rd, 2012 AT 3:09 AM
Tiny
GARYVEEVERS
  • MEMBER
Everything ok there. Tried flushing it through with a hose but it just blows the ends off. Loads of shiny coppery bits in what came out but it did help a bit as the car now has a bit of heat coming out now. Read online it sounds like copperseal which was probably used as a quick fix gone wrong as I did the head gasket when I got it. Trying some caustic soda and warm water in hose to try and blow it through rather than taking whole car apart again. Will let you know if that finally fixes things for me.
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Wednesday, February 8th, 2012 AT 9:35 PM
Tiny
RIVERMIKERAT
  • MEMBER
You may end up having to pull the airbox out from under the dash and put in a new heater core. Let us know what happens. We'll be here.
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Thursday, February 9th, 2012 AT 4:14 AM
Tiny
GARYVEEVERS
  • MEMBER
Ok, update; done matrix, still no better on heater. Radiator bottom hose stone cold. Thinking blocked waterways on actual engine or maybe dodgy new thermostat? Help
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Monday, February 13th, 2012 AT 8:52 PM
Tiny
RIVERMIKERAT
  • MEMBER
I would suspect the thermostat or a clogged radiator. Drain the system into a catch basin/pan and see if water flows readily through it. Especially the radiator. Test the thermostat in a pan of water on the stove with a candy thermometer.
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Monday, February 13th, 2012 AT 9:43 PM

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