2000 Tdi Volkswagen Passat - Air vents not blowing hot air

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Tue 19 Feb 2013 09:43
2000 Tdi Volkswagen Passat - Air vents not blowing hot air - maximusimo
Hi,

for a few months now most of the time my car doesn't blow hot air and even on the rare occasion it does it takes an age for it to happen - e.g. driving for about 20 miles at a constant speed.

Also, the rear footwells on both sides are wet, I know that water comes in through the bottom of the rear passenger door when going through a car wash as have watched this happen - is it a seal on the bottom of the door or what that is the problem here?

Any ideas?
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Tue 19 Feb 2013 09:54
2000 Tdi Volkswagen Passat - Air vents not blowing hot air - Collos25

On modeos water ingress is through damaged door membranes could be the same on Passats,Is it just the heater thats not getting warm ,it could be the main heat control valve that is faulty.On the otherhand its a symptom of a blown Head Gasget.

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Tue 19 Feb 2013 09:58
2000 Tdi Volkswagen Passat - Air vents not blowing hot air - maximusimo

Yeah just the heater and its not fun driving around in this weather with no hot air to warm the inside.

Surely I wouldnt have been able to drive for months if it was the head gasket?

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Tue 19 Feb 2013 11:19
2000 Tdi Volkswagen Passat - Air vents not blowing hot air - Collos25

It sounds from your description like the main heat valve is not working,under the bonnet there should be two pipes going into the cab one should be hot and the other coolish they feed the heater if this is so then the fault is in the cabin under the dashboard,if they are both cold then the problem lies in the engine bay.

Are you sure its not just the fan thats not working if this is the case tempory removal of the cabin filter will increase the airflow into the inside.

Edited by Collos25 on 19/02/2013 at 11:21

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Tue 19 Feb 2013 17:45
2000 Tdi Volkswagen Passat - Air vents not blowing hot air - Mr Fox

Check coolant level, as if its low the heater won't work.

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Wed 20 Feb 2013 09:05
2000 Tdi Volkswagen Passat - Air vents not blowing hot air - maximusimo

Cheers guys,

getting checked out tomorrow so will update then.

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Tue 26 Feb 2013 16:11
2000 Tdi Volkswagen Passat - Air vents not blowing hot air - maximusimo

Have been told to get the thermostat and ect sensor checked, this was meant to be done last week but wasnt able to get it done. Do these two things sound like possible causes and more or less so than coolant?

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Tue 26 Feb 2013 21:11
2000 Tdi Volkswagen Passat - Air vents not blowing hot air - Peter D
What does your temp gauge read. Regards Peter
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Tue 26 Feb 2013 21:11
2000 Tdi Volkswagen Passat - Air vents not blowing hot air - Rob H 85

could possibly be thermostat stuck open or your heater matrix blocked.

does your temp gauge in the car work as normal

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Fri 1 Mar 2013 09:42
2000 Tdi Volkswagen Passat - Air vents not blowing hot air - maximusimo

When car has been going a short while the temperature gauge is fine - straight up at 90 and no further. Leaving car out now to get thermostat replaced

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Fri 1 Mar 2013 11:45
2000 Tdi Volkswagen Passat - Air vents not blowing hot air - Peter D

It is supposed to read 90. It is not a stat problem. Regards Peter

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Fri 1 Mar 2013 13:59
2000 Tdi Volkswagen Passat - Air vents not blowing hot air - maximusimo

i knew in my head it didnt sound right but the mechanic was going by info given to him by my brother and replaced it. Got car back and cant comment on heat as yet as havent driven it for long enough but on way back from garage, about 4 miles, temp gauge went up to 90 as normal but then fell back down and stayed down. Mechanic had put it on his computer and showing no faults.

Any ideas?

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Fri 1 Mar 2013 18:02
2000 Tdi Volkswagen Passat - Air vents not blowing hot air - pd

It is probaly the temp sensor - very common on VAG cars. If you code read it, it will probably have an "intermittant" signal missing code stored for it. Cheap and easy to replace. When the dash doesn't get a signal the gauge just drops and can pop up again when a signal is restored.

My bet on the heater if the car is geeting hot and hot water is getting through to the heater matrix is that one of the servo motors is stuck, particularly if it has climate control. Again, VAG cars are prone to it. The little servo motors which move the flaps about in the heater box go wrong or strip their cogs. The part is not too expensive but can be a nightmare to fit depending on where it is as most of the dash might need to come out.

Edited by pd on 01/03/2013 at 18:03

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Wed 3 Apr 2013 12:40
2000 Tdi Volkswagen Passat - Air vents not blowing hot air - maximusimo

The temp sensor shows no faults when hooked up to a computer. actually it was hooked up to to different ones and neither showed anything.

It seems that the temp gauge normally stays up at 90 when driving in and around town. At this time the vents blow warm air. However, when out on the open road when driving at a consistent speed the temp gauge may fall as does the amount of hot air being blown by the vents.

There is no climate control in the car so doesn't have any servo motors.

Would it be an option to replace the sensor even though its not showing as faulty on computer?

Also, had a rad clean put through so system was flushed and filled with new coolant.

Edited by maximusimo on 03/04/2013 at 12:42

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Mon 3 Jun 2013 14:58
2000 Tdi Volkswagen Passat - Air vents not blowing hot air - maximusimo

Sorry for the late update:

the thermostat has been replaced and it makes no difference. There is also a smell that has come from it a couple of times like as if somethings burning but only lasts a short while and its when turn the temp dial going from cool to hot.

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