No heating

Kleynie

Kleynie

A2OC Donor
So we have little or no heating. We recently changed the coolant and the issues has been present since then I think. Noticed earlier this pipe never gets hot, what is it please?

47568
47569
 
Not familiar with the 1.4 petrol. Is that the location of the thermostat?. If so the stat may be faulty. Do you get heat when the engine is fully up to temperature? Petrol generates a bit more heat than the diesel engine, but in this weather I reach work as the temp gauge reaches 90, so I have less heat than I would like. If not the stat then either a blockage or air lock would be the culprits.
 
We seem to get heat for about 20 seconds each time, then it goes cold (in the cabin). Not made any more progress at the moment other than testing the top hose of the rad gets very hot and the hose pictured above stays cold.
 
This cooling system schematic may help the discussions

Cheers Spike
 

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If the thermostat is located behind that pipe, looking at the bolts fitted I think it is. Then I think the thermostat is stuck and needs an OEM replacement.
 
audifan said:
Yes thermostat is located there, Remove the 2 bolts and check for a blockage if clear replace the thermostat and o ring for a new OEM thermostat.
Also check the hose itself is not obstructed.
Here is the manual

coolant regulator housing; coolant regulator; ther... Audi A2 (A2) 2002 year Audi EUROPA 121075

coolant regulator housing<br/>coolant regulator<br/>thermal switch Audi A2 (A2) 2002 year Audi EUROPA 121075 spare parts
audi.7zap.com audi.7zap.com
Click to expand...
Thank you, I'll add this to my list of things to have a look at.
 
The only thing that I’m thinking is that even if the thermostat is gone the coolant should still heat the cabin. The thermostat only opens and closes the radiator circuit to get the engine hot and then stop it overheating, is that correct? In which case the thermostat has no influence on the cabin heating.
 
Kleynie said:
The only thing that I’m thinking is that even if the thermostat is gone the coolant should still heat the cabin. The thermostat only opens and closes the radiator circuit to get the engine hot and then stop it overheating, is that correct? In which case the thermostat has no influence on the cabin heating.
Click to expand...

If the thermostat was stuck fully open, especially in winter temps the engine would over cool so the heater would never get hot.
I'm assuming the temp gauge shows the engine is getting up to operating temperature.
The schematic shows the heater pipes run from the thermostat housing so can you check if they are getting hot.
If they are, then as far as I know there is no coolant flow control valve to the heater core so cabin temps are principally controlled by the motorised flaps varying the cabin fan airflow through the heater matrix (forget the cabin fan speed controls for now)
Just wondered if you've run a diagnostic scan to check if all the flaps are working correctly

Cheers Spike
 
The engine temps are fine but that pipe never gets hot - seems to go to the bottom of the radiator. But the car is never run for long periods and the bottom hose may we’ll get hot eventually. Something to check I guess.
I’m starting to suspect the flaps are at fault.
 
But as @spike says are the other pipes on the coolant regulator housing getting hot also. Do not know the internals of the block but still think it is a thermostat issue. The flaps even if stuck in the cold position would not have an effect on the coolant hoses. The heater runs full bore with coolant and the temp as spike says is mixed by the flaps. More inclined to think the thermostat is stuck shut or a blockage. For a few quid change the thermostat.
 
Using spikes diagram and the diagram below, the heater feed pipe looks like no 8 and the return no 11, so if no 11 is hot then flow through cabin heater, but still think it is the thermostat at fault
47787
 
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