Heater Blowing Cold

[jbgt2]

Hi All,

 

The heater in the Shalaxy is blowing cold all the time lately. The heater control appears to be working as I can hear the change in the heater itself.

Does anyone know what the issue could be?

How is it fixed?

BTW the air con hasnt worked since I've had the car (4 yrs) so that shouldn't be impacting this recent cold spell (inside and outside the car lol)

 

Thx in advance

[chrispb123456]

Firstly how is the coolant level? does it lose coolant regularly? are both front and rear heater cold.

and which engine do you have?

Galaxy LX is not enough, What year? MK1 or MK2 Petrol or Diesel and engine code

modify your signature to show the above.

[jbgt2]

This is a mk2 1.9 tdi.

coolant level is OK, thats the first thing i checked.

However I didnt check the rear blower heat as I thought the front fed through to the back. Am I mistaken on this?

[chrispb123456]

You have a separate heater unit behind the left hand rear trim panel

 

List of things to check.

 

1. With the engine running can you see coolant returning to the bottle through the small pipe on the side

2. Does the auxiliary coolant pump work (located behind fuel filter) runs all the time engine is running. And for 3 minutes after engine is switched off (AUY code only)

3. Does your booster heater work (jet engine noise from under car)

4. Has your car ever overheated or lost coolant?

[xavier]

This happened to me recently and I was bricking it thinking it was the head gasket or other problem. Turned out it wasn't.

 

First, before you worry about anything else, check the heater control unit is working. Symptoms of it not working are : AC light not lighting up, changing the blower direction knob and it makes no difference, or when it's dark and you switch on your lights, the heater controls don't light up. The blower speed is on a separate circuit, so it will work even if the rest of the unit is dead.

 

If the control unit is working, refer to Chris's list above. It would be useful to know if the engine is hot and you're still getting cold air, or if you've not waited that long. I found mine took an age to blow warm air before I fixed the auxiliary pump, and I'd only get warm air after the engine was hot.

[jbgt2]

OK

 

1. With the engine running can you see coolant returning to the bottle through the small pipe on the side

Yes

 

2. Does the auxiliary coolant pump work (located behind fuel filter) runs all the time engine is running. And for 3 minutes after engine is switched off (AUY code only)

There used to be whirring noise after the engine was switched off. Would that have been this pump?

Anyway there is no whirring noise anymore and the pipe leading to this unit has hot water but the unit doesnt seem to be kicking in.

Will this cause any issues with engine cooling or is it just suppyling heat to the cabin? Should this be an immediate fix?

How hard is the unit to interchange?

 

3. Does your booster heater work (jet engine noise from under car)

Yes

 

4. Has your car ever overheated or lost coolant?

Not since I've owned it

[jbgt2]

Hi Xavier

 

All the heat panel controls seem to work unfortunately the AC hasnt since I owned the car.

Engine is at normal temp and still cold air. I might as well be riding the motorbike lol

 

How did you fix the auxillary pump?

[chrispb123456]

Firstly I remember reading somewhere about disconnecting the power supply to the heater controls and this cured a problem, disconnecting the battery for a few moments should do the same, can't remember what the problem was but it's worth a try.

 

Good news water returning to bottle and that you haven't suffered any loss of coolant and overheating so your engine water pump is working correctly as you can get problems with the impeller breaking off.

 

Auxiliary water pump on the 115 engine is primarily to prevent hot spots after engine switch off and assists with circulation through the booster heater and the rear compartment heater.

 

You say the booster heater is working but without the auxiliary pump working the booster heater will overheat and shut down because of lack of circulation that said and done it doesn't affect the front heater.

 

If you remove the scuttle tray which gives better access to the pump you will also be able to see the hoses going through the bulkhead to the heater can you check these hoses and see if both are hot.

[Russats]

Shouldn't the lower hose be checked also to see if it is running hot or cold? Would it be possible for the stat being stuck open to cause this issue?

 

I'm not expert as you can tell

[xavier]

There's a thread on fixing the aux heater pump in the FAQ. I ordered some carbon brushes (from amazon I think) for a couple of quid. I used the cocktail stick method rather than the cotton thread one.