Heater problems, no heat

[Moonman88]

So I have a 2018 VRS TSI and it's that time of the year where a little bit of heat would help with comfort driving and being able to see out the window, but the car struggles to blow luk warm air, so my initial thought was blocked heater matrix with the problems with the silicon bag but I've pulled the panel off beside the glove box and both pipes are on the matrix are hot so there is plenty of flow there. The next check was the servo to mix the hot and cold and as I turn the temperature wheel it seems to move to either end, so I am assuming it is fine, I've done the calibration of the vents with the AC and front vent button and I'm stuck there scratching head non the warmer, so any help or ideas would be great thanks 

[Moonman88]

Could the matrix be blocked partially and there is enough flow for the water to pass and have 2 hot pipes?

[Ayyarr]

I've got the same problem at the moment.

 

Run engine to temperature, put heating set to 'Hi' and it's cold on the driver's side but lukewarm on the passenger side.

 

Just checked the matrix pipes and the bottom one is almost too hot too touch which I assume in the inlet and the top one is only very lukewarm. I understand it's likely that there is likely to be a disparity between the inlet and outlet - like central heating return but for it to be this much colder I can only assume that there is insufficient flow for the matrix to get hot enough to output heat.

 

I'm not sure if the thermostat could be at fault too but I'm not sure.

 

Edit for info: checked the coolant expansion tank and it's one with the silica bag in and it's still in situ.

Edited 7 December, 2022 by Ayyarr
Info

[Moonman88]

My pipes are both too hot too touch, I couldn't hold them at all, the car gets up to temperature after a few miles,

[Stook]

On 07/12/2022 at 09:33, Ayyarr said:

I've got the same problem at the moment.

 

Run engine to temperature, put heating set to 'Hi' and it's cold on the driver's side but lukewarm on the passenger side.

 

Just checked the matrix pipes and the bottom one is almost too hot too touch which I assume in the inlet and the top one is only very lukewarm. I understand it's likely that there is likely to be a disparity between the inlet and outlet - like central heating return but for it to be this much colder I can only assume that there is insufficient flow for the matrix to get hot enough to output heat.

 

I'm not sure if the thermostat could be at fault too but I'm not sure.

 

Edit for info: checked the coolant expansion tank and it's one with the silica bag in and it's still in situ.

 

Did you get anywhere with this? I'm experiencing similar

 

See this post of mine 

 

 

[Ayyarr]

10 hours ago, Stook said:

 

Did you get anywhere with this? I'm experiencing similar

 

See this post of mine 

 

 

Turns out because I had only had the car for 4 months and not ran it during cold weather - I didn't realise that it was the slowest car on the planet to heat up. The journeys I do are pretty short for the most part during the week with only 1 or 2 that are extended.

 

Long story short, after the car is up to temp, mine heats the cabin fine.

 

After I found this thread it appears to be quite normal (unfortunately!):

 

https://www.briskoda.net/forums/topic/415705-takes-ages-to-warm-up/

[Vahids]

3 hours ago, Ayyarr said:

Turns out because I had only had the car for 4 months and not ran it during cold weather - I didn't realise that it was the slowest car on the planet to heat up. The journeys I do are pretty short for the most part during the week with only 1 or 2 that are extended.

 

Long story short, after the car is up to temp, mine heats the cabin fine.

 

After I found this thread it appears to be quite normal (unfortunately!):

 

https://www.briskoda.net/forums/topic/415705-takes-ages-to-warm-up/

This might be the case for diesel, but pretty sure not for petrol engines unless the thermostats are faulty.

[Ayyarr]

1 minute ago, Vahids said:

This might be the case for diesel, but pretty sure not for petrol engines unless the thermostats are faulty.

Mine in this instance is diesel.

[EnterName]

On 07/12/2022 at 09:33, Ayyarr said:

I've got the same problem at the moment.

 

Run engine to temperature, put heating set to 'Hi' and it's cold on the driver's side but lukewarm on the passenger side.

 

Just checked the matrix pipes and the bottom one is almost too hot too touch which I assume in the inlet and the top one is only very lukewarm. I understand it's likely that there is likely to be a disparity between the inlet and outlet - like central heating return but for it to be this much colder I can only assume that there is insufficient flow for the matrix to get hot enough to output heat.

 

I'm not sure if the thermostat could be at fault too but I'm not sure.

 

Edit for info: checked the coolant expansion tank and it's one with the silica bag in and it's still in situ.

I'm assuming the silica bag is intact and undamaged? (i.e. not leaking)

I read a few of the silica-bag threads on here and got quite concerned about the prospect of my silica bag failing and gumming up my heater matrix, so I whipped it out and later had my my G13 coolant replaced with G12evo.

(The silica bag issue is a bit of a worrying rabbit hole if you start digging, so if your silica bag is okay, probably best to leave that issue for the time being while you sort out your heating problem.)

Example thread:

 

[Ayyarr]

1 minute ago, EnterName said:

I'm assuming the silica bag is intact and undamaged? (i.e. not leaking)

I read a few of the silica-bag threads on here and got quite concerned about the prospect of my silica bag failing and gumming up my heater matrix, so I whipped it out and later had my my G13 coolant replaced with G12evo.

(The silica bag issue is a bit of a worrying rabbit hole if you start digging, so if your silica bag is okay, probably best to leave that issue for the time being while you sort out your heating problem.)

Example thread:

 

 

After reading the forum I had checked the silica bag and it was fully in tact but I have since removed it (coolant was replaced not long ago so no need to do that).

 

When I did call a few places for quotes on a replacement mateix, one chap said that he believes the silica bag is just a coincidence and he's never seen one that's been open when he's had to chance a heater matrix on a MK3 Octavia (VAG specialist garage) 🤷

 

Suffice to say, he said they do replace the old coolant overflow with a new one so is it coincidence?

[EnterName]

6 minutes ago, Ayyarr said:

 

After reading the forum I had checked the silica bag and it was fully in tact but I have since removed it (coolant was replaced not long ago so no need to do that).

 

When I did call a few places for quotes on a replacement mateix, one chap said that he believes the silica bag is just a coincidence and he's never seen one that's been open when he's had to chance a heater matrix on a MK3 Octavia (VAG specialist garage) 🤷

 

Suffice to say, he said they do replace the old coolant overflow with a new one so is it coincidence?

As I said, it's a bit of a rabbit hole and there are differing views on it. My silica bag was undamaged, but I'm a natural worrier, so I fished it out anyway and ended up learning more about VAG coolant than I thought there was to know.

I don't want to derail the thread, but I did want to make sure you could discount the silica bag as a factor with your problem.

Unfortunately I have nothing useful to help Moonman88 with his heating issue.

[Edis85]

I had the exact same problem on my 2015 octavia 1.8tsi, and after taking the heater matrix out for a flush with no effect and checking and removing the silica bag I found the answer on another thread here.

 

After changing the magnetic valve the car feels completely new, heat comes out of the vents after just 1min of driving instead of 20min.

On a sidenote, I almost sent back the part that fixed it because there were two different magnetic valves there, and one of them are different that the one in the thread. But after looking for a second time I found the proper one. 😄😄