Car went in yesterday for heating issues. It was blowing cold air even on high.

 

 Turns out the heater matrix is blocked and needs flushing out. Its a 5 hour job to do. 

 The car is 18 months old FL Vrs and 19000 miles..

 

  What would have caused this? I have never had a car with a blocked heater matrix in 30 years of car ownership.

 

 

Have you had anybody look at the water pump?
Theres another thread which was started recently where RadWeld or some other sealing liquid had blocked the heater matrix.

 

In general it seems like there are a few problems with the heater matrix on the 03 but usually linked with the water pump at least on the diesels anyway.

Hot water wasn't getting to my heater matrix because the coolant check valve on the side of the engine said it was open when it was actually closed.  Bear in mind, if it's the same as my 2015 vRS Petrol that water not circulating through the heater matrix may mean no coolant circulating through the turbo (my turbo went belly up).

 

Is there still a gel sachet in the header tank that can burst and gum things up?

 

Gaz

After 2 days of flushing the matrix at the dealership they have asked Skoda technical for advice again.  

  The matrix is working fine they are now saying but have no idea what is causing the issue of  very little and inconsistent heat. 

Skoda technical have said to change the matrix for a new one.  That did not work. 

 They are looking at the water pump on Monday after taking the hoses off the new matrix with the car running.  No water was going into the matrix. Surprised they did not try that before flushing out the matrix the first time. 

  Be glad when it’s back in my hands and working. 

  

On 15/12/2018 at 00:05, moonwrasse said:

Skoda technical have said to change the matrix for a new one.  That did not work. 

 They are looking at the water pump on Monday after taking the hoses off the new matrix with the car running.  No water was going into the matrix. Surprised they did not try that before flushing out the matrix the first time. 

  Be glad when it’s back in my hands and working. 

  

Hi, I've got a 2013 octavia with similar problems. My mechanic isn't sure if it's the heater matrix. Did they manage to work out what it was?

It turned out it was a faulty flow valve in the end. 

Fair play for answering a revived year old thread so quickly.......

Hi,

 

im having similiar problem to yours.

can you please send me a link to the part you replaced(flow valve)

 

thanks

My 66 plate octavia vrs seems  very slow to start blowing hot air 5-10 mins after 90 degrees reached on water/engine temp gauge. Are these the same symptons as yours? 

As well as the above issues one common problem is IF your car is fitted with a silicat bag (stamped mit silikat on coolant expansion/filler bottle) they have been know to split and the fine grains then block the fine tubes of the heater matrix. Not all engine sizes have this .

 

 

 

Edited 20 February, 20206 yr by bigjohn

Bigjohn, would this silicat problem cause the blower to blow cold all the time or the problem to be intermittent?

Cheers 

On 20/02/2020 at 21:45, Coops004 said:

My 66 plate octavia vrs seems  very slow to start blowing hot air 5-10 mins after 90 degrees reached on water/engine temp gauge. Are these the same symptons as yours? 

yes excacly my symptoms.

 

i have silicat  bag but i checked and its not blowend.

just removed my silicat bag, still intact

Im happy to say problem fixed for me.

 

in the end it was the flow valve.

after replacing this part my Heater worked 1-2 min after car started.

 

the flow valve apparently being stuck close and open late when car drive few miles.

 

apparently only 1.8 and 2.0 tsi and tdi engines have this part installed.

 

 

Part number is:
4HC 121 671 D

 

Hope this helps others in the future.

Great cheers. Was it easy to fit?

about 20 min work in the workshop.

 

its on the right side of the engine.

 

the big box next the engine will block your way i think its the air filter box, so after removing it you need remove 2 screw then release the 2 hoses connected and connector and replace with new valve.

 

look at the photo, big circle is the plastic box need to be remove and the small circle is where the valve found.

Edited 24 February, 20206 yr by Ronaldo131

Cheers, will give it a go when i have a bit of time 👍

Quick update. Mine was booked into the stealers for tomorrow but has been working great since sunday so i cancelled. Will re book in if the problem reoccurs

did you notice any change in engine temperature with the check valve closed?  I've a 2014 tsi vrs which slowly slowly, year on year the normal engine running temp has been climbing.  It was  ~102/103C oil temp when new and now its usually ~108C.  I wonder if my check valve is getting more and more sticky?  I also thought the cabin wasn't as warm as it should be a couple of times recently, not completely cold, but didn't comfy until I dialed in a temp a degree or more warmer than normal....I put it down to just getting old!  Now I'm thinking it might be worth changing the check valve.  what is the cost of the part please?

No idea on the cost neiln. My temp just  goes up to 90 and stays there but it seems when the cabins not heating properly the temp rises faster (coolant valve i assume is sticking shut) and when its heating normally the temp gauge still rises to 90 but takes a bit longer (i assume with the valve open theres more water to heat so takes slightly longer). I wouldnt have thought that valve would have any effect over your actual water temp as its just purely a shut off valve to the matrix, water round the engine is unaffected.  If that makes sense. I could of course be completely wrong 🤣🤣🤣

Sorry, I meant oil temp, I was (am) guessing with no water cooling the turbo the oil temp might be somewhat higher.

I remember when my heater matrix blocked, the oil would sit at about 102 when on the motorway (70 on cruise control). If climbing any sort of gradient (additional engine workload), it would climb as high as 112 for a brief period. It previously had sat at 92 on the motorway (even across France at 130kph in 30 degree heat for hours on end), it'd sit happily at 92 degrees. When the heater matrix blockage was cleaned and the matrix replaced, the oil quickly settled back in to the 92 degrees normality again (maybe the oil heat exchange was contaminated also, hence poorer coolant performance). The engine temperature gauge has never gone above 90 in my time of owning the car.

 

from what iv been told the valve shutoff  are also for the turbo cooling.

another thing that also happend for me is that the auxiliary water pump(secondary water pump) was working to cool the turbo for 10min or more each time i turn off the engine.

i know its should do its job each time(for small amount of time) but i remembered it wasnt that long.

 

apperantly i was right cause after changing the valve the auxiliary water pump only runing for a minute or less until its finish to cool the turbo.

 

if your using the car heater when the valve open vs closed i think it should be few celcius less in the oil temparture as the water flow in the matrix will get ventilated.

 

my car was runing 106C  now its not more then 102C maybe coincidence maybe not.

The valve is about £135 for a genuine part. Lopks like it is only for the the TSi engines and not TDi according to Skoda Parts website.