Blowers in the cabin blow cool when on high
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AudiWorld Newcomer
Joined: Aug 2018
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Blowers in the cabin blow cool when on high
Recently had a water pump failure and had the water pump and belts replaced but when I had the car back the garage said the water will not go through the matrix with the bottom hose being very hot and top cold where it goes through the bulkhead.
I have tried bleeding the system using the hole in the top hose but no joy. The hot water does not seem to go through the heater matrix but the temp is on 90 and looks normal on the gauge.
any help is very grateful
I have tried bleeding the system using the hole in the top hose but no joy. The hot water does not seem to go through the heater matrix but the temp is on 90 and looks normal on the gauge.
any help is very grateful
Audiworld Junior Member
Joined: Mar 2017
Posts: 9
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As a first test. I would disconnect both heater matrix pipes and force water through it both ways using a garden hose. It may be blocked.....hopefully or else.
what engine have you got? If it’s the 2.0 ALT. There are 2 other things that can cause this. 1 you have lots of air in the system. Bleed both the heater matrix upper hose and also the top pipe by the injectors. It took me ages to get all the air out of mine.
2 The cylinder head gasket on the 2.0ALT is prone to failure between cylinders 3 and 4 (on th factory head gasket) around 60-70k seems to be a common time.
This fault happened with mine exactly as you are describing it. First I started losing heat in the cabin. Tried several bleeds of heater matrix. Top pipe always cold. Bottom pipe was warm. Temp gauge always read correctly (90) then over the course of a few weeks it then had odd temperature fluctuations for a couple of seconds then would be ok for another 50 odd miles (still no cabin heat). Finally after a full Audi service (at Swindon Audi - not my favourite dealership) I received it back with a head full of mayonnaise). Seems the head gasket finally went during the service and they never noticed.
If if yours starts doing these things and You have definitely bled the water system.
Then try this
Drive the car till radiator pressurised.
turn car off.
Take out spark plugs (assuming it’s a petrol) and leave over night.
Check cylinders in morning with a torch and see if there is any water in them.
Hope his helps.
what engine have you got? If it’s the 2.0 ALT. There are 2 other things that can cause this. 1 you have lots of air in the system. Bleed both the heater matrix upper hose and also the top pipe by the injectors. It took me ages to get all the air out of mine.
2 The cylinder head gasket on the 2.0ALT is prone to failure between cylinders 3 and 4 (on th factory head gasket) around 60-70k seems to be a common time.
This fault happened with mine exactly as you are describing it. First I started losing heat in the cabin. Tried several bleeds of heater matrix. Top pipe always cold. Bottom pipe was warm. Temp gauge always read correctly (90) then over the course of a few weeks it then had odd temperature fluctuations for a couple of seconds then would be ok for another 50 odd miles (still no cabin heat). Finally after a full Audi service (at Swindon Audi - not my favourite dealership) I received it back with a head full of mayonnaise). Seems the head gasket finally went during the service and they never noticed.
If if yours starts doing these things and You have definitely bled the water system.
Then try this
Drive the car till radiator pressurised.
turn car off.
Take out spark plugs (assuming it’s a petrol) and leave over night.
Check cylinders in morning with a torch and see if there is any water in them.
Hope his helps.
Thread Starter
AudiWorld Newcomer
Joined: Aug 2018
Posts: 3
Likes: 0
As a first test. I would disconnect both heater matrix pipes and force water through it both ways using a garden hose. It may be blocked.....hopefully or else.
what engine have you got? If it’s the 2.0 ALT. There are 2 other things that can cause this. 1 you have lots of air in the system. Bleed both the heater matrix upper hose and also the top pipe by the injectors. It took me ages to get all the air out of mine.
2 The cylinder head gasket on the 2.0ALT is prone to failure between cylinders 3 and 4 (on th factory head gasket) around 60-70k seems to be a common time.
This fault happened with mine exactly as you are describing it. First I started losing heat in the cabin. Tried several bleeds of heater matrix. Top pipe always cold. Bottom pipe was warm. Temp gauge always read correctly (90) then over the course of a few weeks it then had odd temperature fluctuations for a couple of seconds then would be ok for another 50 odd miles (still no cabin heat). Finally after a full Audi service (at Swindon Audi - not my favourite dealership) I received it back with a head full of mayonnaise). Seems the head gasket finally went during the service and they never noticed.
If if yours starts doing these things and You have definitely bled the water system.
Then try this
Drive the car till radiator pressurised.
turn car off.
Take out spark plugs (assuming it’s a petrol) and leave over night.
Check cylinders in morning with a torch and see if there is any water in them.
Hope his helps.
what engine have you got? If it’s the 2.0 ALT. There are 2 other things that can cause this. 1 you have lots of air in the system. Bleed both the heater matrix upper hose and also the top pipe by the injectors. It took me ages to get all the air out of mine.
2 The cylinder head gasket on the 2.0ALT is prone to failure between cylinders 3 and 4 (on th factory head gasket) around 60-70k seems to be a common time.
This fault happened with mine exactly as you are describing it. First I started losing heat in the cabin. Tried several bleeds of heater matrix. Top pipe always cold. Bottom pipe was warm. Temp gauge always read correctly (90) then over the course of a few weeks it then had odd temperature fluctuations for a couple of seconds then would be ok for another 50 odd miles (still no cabin heat). Finally after a full Audi service (at Swindon Audi - not my favourite dealership) I received it back with a head full of mayonnaise). Seems the head gasket finally went during the service and they never noticed.
If if yours starts doing these things and You have definitely bled the water system.
Then try this
Drive the car till radiator pressurised.
turn car off.
Take out spark plugs (assuming it’s a petrol) and leave over night.
Check cylinders in morning with a torch and see if there is any water in them.
Hope his helps.
Audiworld Junior Member
Joined: Mar 2017
Posts: 9
Likes: 0
They are notorious to bleed properly. I eventually had to get mine pressure bled by Audi (after I had replaced the gasket, skimmed and pressure tested the head).
They seem to get air locks if you drain the head down (as you have done with replacing the pump). The water system was designed by a lunatic it seems.
If you disconnect the bottom heater matrix hose, is there any flow from it?
They seem to get air locks if you drain the head down (as you have done with replacing the pump). The water system was designed by a lunatic it seems.
If you disconnect the bottom heater matrix hose, is there any flow from it?
Thread Starter
AudiWorld Newcomer
Joined: Aug 2018
Posts: 3
Likes: 0
They are notorious to bleed properly. I eventually had to get mine pressure bled by Audi (after I had replaced the gasket, skimmed and pressure tested the head).
They seem to get air locks if you drain the head down (as you have done with replacing the pump). The water system was designed by a lunatic it seems.
If you disconnect the bottom heater matrix hose, is there any flow from it?
They seem to get air locks if you drain the head down (as you have done with replacing the pump). The water system was designed by a lunatic it seems.
If you disconnect the bottom heater matrix hose, is there any flow from it?
Audiworld Junior Member
Joined: Mar 2017
Posts: 9
Likes: 0
Have you taken the top pipe off completely?
when the water pump failed did it crack or was it in one piece?
When bleeding the water system. Are you disconnecting the header tank and making it higher than the heater matrix (something Audi specify to do)
the logic for this test is: If water is coming out of the bottom pipe,
then when connected,
water comes out out the top heater matrix outlet then something after the top outlet is preventing flow.
If the top pipe is disconnected and no flow comes out of the matrix(even when revved),
then there is not enough flow from the lower pipe.
when the water pump failed did it crack or was it in one piece?
When bleeding the water system. Are you disconnecting the header tank and making it higher than the heater matrix (something Audi specify to do)
the logic for this test is: If water is coming out of the bottom pipe,
then when connected,
water comes out out the top heater matrix outlet then something after the top outlet is preventing flow.
If the top pipe is disconnected and no flow comes out of the matrix(even when revved),
then there is not enough flow from the lower pipe.
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