Not getting any heat through car heater. Possible causes?

kissenger · 21 Dec 2019 at 17:26

My car (a 2013 Octavia) heater seems to have gradually got worse over the roughly three years I've had it, to the point where it takes ages to get any heat and I have to start my morning commute with fogged windows. I've checked the engine coolant levels and they seem fine, and the engine temperature has never been a problem, so I don't think it's that.

What else could it be? Would a coolant flush/replacement be likely to sort it?

b00merang69 · 21 Dec 2019 at 17:28

Thermostat (check your temp gauge see if normal range when car heat up), not sure on your car but it is usually a wax filled unit.

jpaul · 21 Dec 2019 at 17:38

failing (electrical) solenoid valves controlled by hvac system that route the hot coolant through heating matrix for left & right of car .. leastways they do on bmw

SeatIbiza · 21 Dec 2019 at 17:50

I presume air con - have you had this checked?

bainbridge · 22 Dec 2019 at 07:45

Your heating problems sound like a stuck open thermostat.

Heisenberg · 22 Dec 2019 at 09:05

How does the coolant look? They are bad for contaminated coolant from the way the system was manufactured which can gradually contaminate. If it's a browny colour instead of pink, then it will be a blocked heat exchanger causing your issue. Requires removal of the heat exchanger, clamp the hoses, full extensive coolant flush, and I'd also recommend replacing the heat exchanger though they can be flushed it's a complete pain.

IAmATeaf · 22 Dec 2019 at 12:38

If the coolant temps are OK and the car gets to temperature as normal then check to see if there is a solenoid.

On my old Honda it had a solenoid which when triggered would allow the coolant into the heater matrix, that slowly packed up so would get stuck in the cold position.

Brookert · 23 Dec 2019 at 08:03

If your temps are ok. Your heater matrix is probably blocked up with crud and needs flushing.

I did it with just a garden hose blasting crap out opposite to the way the coolant normally flows.

Armageus · 23 Dec 2019 at 08:19

Has the Pollen filter ever been replaced?

Jamesyboyjim · 24 Dec 2019 at 12:17

bainbridge said:
Your heating problems sound like a stuck open thermostat.

It does, but op says the coolant heats up.

Op, if you leave the car idling does it eventually warm up but if you drive, does the temp drop again?

kissenger · 9 Jan 2020 at 22:00

Sorry for delay in responding. Ended up getting it seen by Skoda who said that it was caused by a contaminated coolant reservoir. Nothing broken, just gunk from gradual corrosion over the years. I should have been getting the cooling system serviced, but I neglected it.

Anyhow, they quoted me £500 to get it fixed. Mainly on the basis of labour costs alone, because it apparently takes four hours to drain it and with stealership labour rates...

Anyone had this problem before? How much did it cost you? Is it the sort of thing I should be worried about long term or will there be no lasting damage if I get it sorted?

wedrum · 9 Jan 2020 at 22:11

£500 to drain the system.
I would be taking it somewhere else.

kissenger · 9 Jan 2020 at 22:23

wedrum said:
£500 to drain the system.
I would be taking it somewhere else.

That’s what I thought. Will ring around tomorrow but was wondering what sort of prices I should expect.

sideways14a · 9 Jan 2020 at 22:25

Help ma bob 500 notes to clean out the cooling system.
Diy job that surely, pull off the rad pipe and stuff a hose into one side and a bucket on the other - you can get cleaner for it as well.

kissenger · 9 Jan 2020 at 22:30

sideways14a said:
Help ma bob 500 notes to clean out the cooling system.
Diy job that surely, pull off the rad pipe and stuff a hose into one side and a bucket on the other - you can get cleaner for it as well.

I’ve even got the part number for the VW cleaner I need. I would screw it up though so I won’t touch it.

sideways14a · 9 Jan 2020 at 22:31

Really hard to screw something like this up, although if it was still under warranty i would get it done by a garage.

Jonnycoupe · 9 Jan 2020 at 23:19

Just need to understand if they might be a certain filling process/hidden bleed points to avoid airlocks.

jpaul · 10 Jan 2020 at 08:42

depending on car age, maybe they would be replacing radiator tubes as well, the internal car heater matrix can be decoupled and probably has to be flushed separately,
(solenoid valves link it)
I know mine is a pita, so I can see how they arrive at a large quote.

I'd get some quotes at an independant too for a 'basic' flush.

The-Plethora · 10 Jan 2020 at 09:56

I remember cleaning out my heater matrix with a bottle of Mr Muscle and a hosepipe, worked great.

kissenger · 10 Jan 2020 at 10:29

jpaul said:
depending on car age, maybe they would be replacing radiator tubes as well, the internal car heater matrix can be decoupled and probably has to be flushed separately,
(solenoid valves link it)
I know mine is a pita, so I can see how they arrive at a large quote.

I'd get some quotes at an independant too for a 'basic' flush.

I think the £500 was just a basic clean because I asked for a detailed breakdown of what they would do and they didn’t mention anything more specialist. I asked about replacement parts and they said nothing would need replacing (except coolant obviously).