Mk3 Polo 1.4 - Heater blowing no hot air at all

[neil_bolton]

Yoyoyo VW Guru Josh's:

My missus has a R reg 1.4 Polo Mk3, and has been pretty reliable.

However the heater has decided to stop blowing hot air:

• It blows on all settings
• The pipes leading to the heater matrix are hot
• The temp adjuster does seem to be changing the heater matrix setting
• Thermostat seems fine, bang on middle, no overheating issues
• Car has not had any work done recently (i.e. no head gasketr anything requiring coolant)

I've read that there may be some air in the coolant system, and that bleeding the system till the bubbles stop and just water comes out.

Tried to find the bleed screw based on the instructions and guess its under the plastic engine cover? Gave up 10 minutes ago based on the cold hands I'd gained but will take another look tommorrow, but was wondering if anyone can confirm what it could be?

I guess it could be a buggered heater matrix?

Ta muchly VW geeks

[neil_bolton]

Moving this out here in a blatant abuse of Mod powers to see if I can get some form of answer

After all, the missus is moaning at me to fix it

[sniff diesel]

Could you try flushing the cooling system?

[neil_bolton]

sniff diesel said:

Could you try flushing the cooling system?

I could but I haven't - it was only pointed out to me yesterday, and I only had a dark, sleety cold road to poke about under the bonnet...

[crofty1984]

Head gasket gone, all water shot/boiled out. That's what happened in my old polo. Maybe.

[neil_bolton]

crofty1984 said:

Head gasket gone, all water shot/boiled out. That's what happened in my old polo. Maybe.

If that were the case I wouldn't be getting warm pipes, and she'd have ground to a halt by now with an overheated car.

She doesn't know where the water goes in, so she'd never top the coolant up...

[cheesesliceking]

HG unlikely, more likely to be broken or stuck thermostat.

[neil_bolton]

cheesesliceking said:

HG unlikely, more likely to be broken or stuck thermostat.

You reckon? Water temp gauge sits bang on middle once engine at running temp, and doesn't move?

[neil_bolton]

anonymous said:

[redacted]

I've read the same - apparantly there is a bleed pipe on the matrix that allows you to get rid of any air in the system - but I wasn't able to find it last night...

ETA: This is what I read: http://www.clubpolo.co.uk/forum/index.php?showtopi...

Edited by neil_bolton on Wednesday 29th October 08:55

[crofty1984]

neil_bolton said:

cheesesliceking said:

HG unlikely, more likely to be broken or stuck thermostat.

You reckon? Water temp gauge sits bang on middle once engine at running temp, and doesn't move?

In that case, blows my "no water" theory away. I might have a granola bar.

[neil_bolton]

anonymous said:

[redacted]

Excellent my thinking too, as have gone through all the above, including ensuring that the adjuster actually changes the temp flow.

Will have another look tonight

[neil_bolton]

Just been told it could be the Heater Motor Resistor...?

This is from a VAG parts guy, so he'd pretty clued up...

[OJ]

Might be a silly answer, but does it have a flap to mix the hot air with the fresh air? If yes then is it flapping?

[Deva Link]

neil_bolton said:

Just been told it could be the Heater Motor Resistor...?

This is from a VAG parts guy, so he'd pretty clued up...

That's a common fault, but it stops the heater blower from working on all but the fastest speed. You said the fan worked OK.

[neil_bolton]

Deva Link said:

neil_bolton said:

Just been told it could be the Heater Motor Resistor...?

This is from a VAG parts guy, so he'd pretty clued up...

That's a common fault, but it stops the heater blower from working on all but the fastest speed. You said the fan worked OK.

Oh bum. I'll throw it back at him.

The flap seems to work, as I had a careful 'test' yesterday, and it seems to change the flow of air...

[...Mole...]

I had the same problem in my Mk4 1.4 TDi. It turned out to be something to do with the water pump, i cant quite remember why that affected the heating but i ignored it for a few days only to notice my car overheating about 200 miles from home. Needed a new water pump fitted cost about #115.

Dont know if thats the same problem you are having but its maybe worth getting it checked out.

[3sixty]

...Mole... said:

I had the same problem in my Mk4 1.4 TDi. It turned out to be something to do with the water pump, i cant quite remember why that affected the heating but i ignored it for a few days only to notice my car overheating about 200 miles from home. Needed a new water pump fitted cost about #115.

Dont know if thats the same problem you are having but its maybe worth getting it checked out.

The plastic impellors are prone to breaking. You can get the updated metal one.