GolfGTIforum.co.uk
Model specific boards => Golf mk7 => Topic started by: 2007GTI on 26 November 2025, 18:24
-
So this issue has been going on for years, if you put the heat on, it only comes out of the far side passenger face height vent. It gets a little bit hot on other vents, but will not blow out hot air, even if redirected.
Last year I replaced one of the temp flat motors and also the additional water pump which cleared the error, but I still only have hot air coming out of the far passenger vent. It’s been bugging me so I finally got my trusted mechanic to pull the dash apart, thinking it might be another flap actuator.
After pulling the dash out and flushing the system, he tells me:
I can’t find anything obvious, all flaps and motor working how they should. No fault codes in the climate control module. I’ve flushed the matrix and hasn’t made any difference either.
So anyone got any ideas?
-
Had exactly the same on my Audi A3 (8V). Heater matrix required replacing. Do you have the Silica bag in your coolant expansion tank, is it intact?
-
Coolant Bottle was replaced under warranty when 3 years old, just after I bought it, as it used coolant. They probably did water pump etc, but I was never made aware, the problem was fixed. This was 8 years ago.
1 year ago I took the bag out and it was not damaged.
I read reports from folk online with same issue and they said that they had the matrix replaced and was no different. Also both pipes going in and out of matrix are burning hot, makes no sense!
-
Having a similar issue with my GTI whereby the passenger side vents can blow out nice hot air but all those on driver’s side won’t get any more than tepid.
Tried doing the A/C reset trick but that didn’t make any difference.
Took it to dealership who said that heater matrix needs replacing but that wouldn’t be covered by the All-In extended warranty; unlike the thermostat housing which got replaced a few years ago when there was a coolant leak and they removed the dreaded silica bag.
-
Thanks, that is the only likely culprit left, so will probably end up changing it.
Having a similar issue with my GTI whereby the passenger side vents can blow out nice hot air but all those on driver’s side won’t get any more than tepid.
Tried doing the A/C reset trick but that didn’t make any difference.
Took it to dealership who said that heater matrix needs replacing but that wouldn’t be covered by the All-In extended warranty; unlike the thermostat housing which got replaced a few years ago when there was a coolant leak and they removed the dreaded silica bag.
-
https://m.youtube.com/watch?v=WjvPcXs9muo&pp=ygUXIFZ3IGdvbGYgaGVhdGVyIHByb2JsZW0%3D
Interesting watch and may help with your diagnosis
-
Maybe query that they've turned you down under the All-in plan, I've got the same issue and mine is going in on Wednesday to my dealer and all of the work is being covered with the All-in warrantee. They have allocated three days so fingers crossed I'll have it back on Friday although they did initially have it back twice to test and take readings which they submitted before okaying the work.
-
Having a similar issue with my GTI whereby the passenger side vents can blow out nice hot air but all those on driver’s side won’t get any more than tepid.
Tried doing the A/C reset trick but that didn’t make any difference.
Took it to dealership who said that heater matrix needs replacing but that wouldn’t be covered by the All-In extended warranty; unlike the thermostat housing which got replaced a few years ago when there was a coolant leak and they removed the dreaded silica bag.
I’d check the small print in the All In warranty. If you can’t see the heater matrix is excluded then I’d ask the dealer to show you where in the warranty documentation it’s excluded.
-
Maybe query that they've turned you down under the All-in plan, I've got the same issue and mine is going in on Wednesday to my dealer and all of the work is being covered with the All-in warrantee. They have allocated three days so fingers crossed I'll have it back on Friday although they did initially have it back twice to test and take readings which they submitted before okaying the work.
I’d check the small print in the All In warranty. If you can’t see the heater matrix is excluded then I’d ask the dealer to show you where in the warranty documentation it’s excluded.
Marshalls closed my local dealership (who’d done a few previous repairs under warranty) in the spring, so I had to schlep about 45 minutes to nearest VW branch. I might’ve to trek up to the larger branch in Milton Keynes for a 2nd opinion if it is such a common fault which is typically covered then.
https://m.youtube.com/watch?v=WjvPcXs9muo&pp=ygUXIFZ3IGdvbGYgaGVhdGVyIHByb2JsZW0%3D
Interesting watch and may help with your diagnosis
I was also told it’s a 3 day job by dealership but local independent VW garages seem to think the matrix can be replaced in a day and judging by that video the latter seems realistic.
-
Yes, it's a 1 day job to change the heater matrix, VW stealers are taking the pi$$.
-
not relevant post - deleted
-
Very odd isn't it with the sand like gunk - if it's casting sand then surely that would potentially affect 10's of thousands of VW vehicles - something doesn't add up to me.
-
To be honest i haven’t seen it in person yet, will do when i pick the car up, but it sounds the same. The coolant looked normal in the bottle!
My mechanic said he talked a lot of VW folk and they said they do a lot of heater matrix, and from what I’ve found online I believe them.
-
Update, I had the heater matrix replaced and it has cured my issue, heater blowing hot on all vents and even before car is fully up to temp. So I am very happy as this has been going on for ages.
Mechanic charged me 6.8 hours labour, which he said is the book price, and he is £50 per hour, then a bit on top for flushing etc.
I bought a third party matrix as I needed it quick and GSF could get me this one same day, which was fine:
https://www.gsfcarparts.com/products/heater-matrix-avavn6424
FYI mine was denso type.
It didn't come with new clamps and O rings, old ones were shot, but local stealer had them in stock for £25, cheaper than ebay and same day.
Picture below of old one with the brown gunk, not as bad as that Youtube link, but still not great.
(https://i.ibb.co/cdW7rX2/Screenshot-2025-12-02-at-20-57-17.png) (https://ibb.co/cdW7rX2)