1996 Audi A4 Bubbles in Heating system

WORKDRAGON

MEMBER
1996 AUDI A4

Heater problem
1996 Audi A4 6 cyl All Wheel Drive Manual

I love my audi but I really would love it more with heat. Before I replace the heater core which involves hours of dash removal, I thought I might ask. I flushed the coolant and replaced it with audi approved coolant. Replaced the climate control system. I bleed the system using the screw on the block as well as the outlet hose on the firewall. When I bleed the system with the hose at the firewall I see bubbles of coolant/air that never seem to end. I believe that I have air in the system but where on a closed system like audi's could I look? Does anyone have a heating diagram for it? How can I have a place where air can get in but have no coolant leaks?

9 Replies

2CARPRO JACK

MECHANIC
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Does the car ever overheat? If it has never ending air bubbles, they could be generated by a head gasket that is leaking. Take it to a shop and have them do a chemical test for the prescence of exhaust gasses in the cooling system to rule this out. It could have caused the heater core failure in the first place by over pressuring the system

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Friday, October 3rd, 2008 AT 7:57 AM

WORKDRAGON

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Thanks for a fast response. Oh, BTW, I forgot I have also replaced the radiator, always use OEM parts, just fyi. The car has never over heated and I dont have a loss of coolant.

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Friday, October 3rd, 2008 AT 9:28 AM

2CARPRO JACK

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Then you might want to try waiting til the thermostat opens then crack the bleeder to see if you can purge the air out. There isnt any other place air can be generated within a sealed cooling system. Glad to hear you only use OE parts, very smart

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Friday, October 3rd, 2008 AT 9:39 AM

WORKDRAGON

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Thanks will try and do some further pruging. I did notice this morning I bleed the system for about 10 minutes straight using the hole on top of the outlet hose, that I did recieve an increase in heating temp from the vents in the car. After the car returned to cold and was brought back normal operating temp the progress in temp was lost. Thanks again for all the help, it really helps getting the advance from a pro.

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Friday, October 3rd, 2008 AT 10:28 AM

2CARPRO JACK

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Let me know how it goes

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Friday, October 3rd, 2008 AT 6:48 PM

WORKDRAGON

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Warm air comes out of the vent after purging at operating temp. Warmer air comes out of the defrost vent then the dash vents after purging. I set the ecc at 85 but it blows around maybye 70. I am thinking that I might also have a problem with the bind door not letting enough hot air to the forward vents. I do hear the door open and close with temp movement. Since I am going to replace the heater core in two weeks, I am going to do removal in stages. First glove box and center console this tuesday will give me a look at the doors. Cheers. Will let you know and thanks

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Friday, October 3rd, 2008 AT 10:09 PM

2CARPRO JACK

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Have fun.

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Saturday, October 4th, 2008 AT 7:47 AM

WORKDRAGON

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Update: The last few weeks have been busy. I replaced the Heater core, the water pump, thermostat, and belts. I Waited untill the system incresed to operating temp and bleed the system. I removed the hose comming out of the heater core and nothing came out! I rev the engine and coolant came out but I am lacking pressure. Any ideas of where to look

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Wednesday, February 4th, 2009 AT 2:01 PM

2CARPRO JACK