Aircon and heater doesn't work
- Thread starter Scott_FR
- Start date
2 weeks??? Wow! You're going to be pissed off when I get the time to post my conclusion then!
A few weeks after the baby arrived, I managed to slip outside for a few hours. Thought seeing as I had some success previously with flushing the coolant, i'd give it another go. Basically drained the coolant, removed the two matrix pipes from the firewall, then proceeded to flush with water. It again didn't seem to flow well initially, but after a little pressure, it seemed to flow well. Had what I thought would be a genius idea, and fired some compressed air in as well for good measure.
Tried some Holts speedflush, this time pouring it all directly into the matrix using my pipe arrangement. Then followed a long and painful process of filling with water, getting car up to temperature, draining more fluid, refilling, getting back up to temperature, etc. Long story short, I managed to get heat back into the cabin, but not much.
So after a few hours of all this fannying about, and with soaked shoes and clothes from all the watery goings on, I came to the conclusion that I was up shat creek without a paddle. The matrix was going to have to come out. :-(
Having read on here about someone who had to send their car back to the dealers for 6 days, and many threads on the internet about various VAG cars needing their whole dashboard ripped to pieces to access the matrix - I set about the task.
I had noticed what I thought to be a matrix pipe hidden under the dash when pulling the glovebox down when I had changed my pollen filter recently, but there was no access there at all.
So first job was to remove the whole glovebox assembly - you can see a pipe here which I suspected to be the matrix:
Looking at it, it seemed to get to the matrix, i'd have to get the centre console out. To do that, it looked like the whole thing would need to move.
So I set about ripping the car to pieces...
And the end result of the teardown...
It wasn't until this last stage that I realised the 'lower skirts' of the centre console are separate, and can be removed with just a single screw in the footwell. More on this later!!!
But after all this, I could finally see that this was indeed the heater matrix. You can see the hot feed and return pipes here:
And at this stage... it also appeared clear that it should actually just slide out towards the passenger side footwell, ie: the motherflippin' centre console, HVAC unit, etc. didn't need to come off at all!
On closer inspection, perhaps I shouldn't have fired pressurised air down into the matrix which usually probably doesn't see a huge pressure! Note the wetness of coolant - thankfully only a very small amount, and the carpets and foam around were all dry, proving at least that the matrix itself wasn't leaking (and I haven't been losing coolant):
I also found the reason behind the asthmatic delivery of air from the vents...
But, with a new baby in the house, my time was up for the day.
Removing the matrix would need to wait until the next day...
Tried some Holts speedflush, this time pouring it all directly into the matrix using my pipe arrangement. Then followed a long and painful process of filling with water, getting car up to temperature, draining more fluid, refilling, getting back up to temperature, etc. Long story short, I managed to get heat back into the cabin, but not much.
So after a few hours of all this fannying about, and with soaked shoes and clothes from all the watery goings on, I came to the conclusion that I was up shat creek without a paddle. The matrix was going to have to come out. :-(
Having read on here about someone who had to send their car back to the dealers for 6 days, and many threads on the internet about various VAG cars needing their whole dashboard ripped to pieces to access the matrix - I set about the task.
I had noticed what I thought to be a matrix pipe hidden under the dash when pulling the glovebox down when I had changed my pollen filter recently, but there was no access there at all.
So first job was to remove the whole glovebox assembly - you can see a pipe here which I suspected to be the matrix:
Looking at it, it seemed to get to the matrix, i'd have to get the centre console out. To do that, it looked like the whole thing would need to move.
So I set about ripping the car to pieces...
And the end result of the teardown...
It wasn't until this last stage that I realised the 'lower skirts' of the centre console are separate, and can be removed with just a single screw in the footwell. More on this later!!!
But after all this, I could finally see that this was indeed the heater matrix. You can see the hot feed and return pipes here:
And at this stage... it also appeared clear that it should actually just slide out towards the passenger side footwell, ie: the motherflippin' centre console, HVAC unit, etc. didn't need to come off at all!
On closer inspection, perhaps I shouldn't have fired pressurised air down into the matrix which usually probably doesn't see a huge pressure! Note the wetness of coolant - thankfully only a very small amount, and the carpets and foam around were all dry, proving at least that the matrix itself wasn't leaking (and I haven't been losing coolant):
I also found the reason behind the asthmatic delivery of air from the vents...
But, with a new baby in the house, my time was up for the day.
Removing the matrix would need to wait until the next day...
First job was to get the lower section of the blower out, as I needed to repair the cracked plastic to allow to seal.
Bodged up a little 'tool' to catch and drain the coolant from the matrix.
As you can see from the pic, the bottom hose is just held on by a pipe clip with a single screw. Took quite a decent tug to get the pipe free, but when it did, I was surprised how little fluid came out. Probably no more than a few hundred mls, but rather have it outside than underneath the carpet!.
The top hose is held in place by a simple clip which can just be pulled out. Again, the hose was in there pretty well. More tugging!
Once both hoses were off, there is a plastic cover over the matrix, held in by 2 torx bits. Once they are removed, the cover can be removed. Think it was hinged from the top.
Tada! Can finally see the matrix in all its glory.
With all that out of the way, the matrix just slides out nicely.
When the matrix was out, it looked pretty much brand spanking new, except for a few bent fins (probably from removal). Why wouldn't it, it lives out of sight its whole life. This alone would make me avoid buying a second hand heater matrix.
Anyway, I stuck a garden hose inside it (fits perfectly inside the ports) and noticed that the flow really was pretty poor. Gave it a good fews goes each way, but it was squirting more out of the side I was hosing it in from. Blowing through it like a cheap trumpet was tough on the lungs. Had read on the internet that people have had success with cleaning matrixes using dishwasher powder. I drained the matrix, crushed up a dishwasher tablet, then proceeded to fill the matrix with boiling water from the kettle. Took ages to fill from one side, which was expected given I knew it seemed clogged up. I made some makeshift bungs for each side using cling film and kitchen towels, one down each port. Then I was able to give it a good shake. Left it about an hour in total. Flushing it through afterwards, you could see the water was flowing much better now. And 'the trumpet test' (TM) certainly seemed a lot easier! :-D
Took it back outside and gave it a good few flushes each way with the garden hose. Definitely flowing better.
But there was loads of water stuck in the fins from all my hosepipe shenannigans. Didn't want to put the matrix back in like this, as all that would happen is this water would end up misting up my windows until it was all gone. So a little ingenuity...
Refitted the matrix, put the plastic cover back on - being careful to refit the rubber gasket, reattached the 2 screws holding the cover, refit the hoses and reattached the clips. Filled the header tank with water and started the engine to let it get up to temperature.
It was at this point, I noticed the lower matrix hose leaking!
No drama though, it was just not seated correctly. Drained the matrix again (make sure you remove the hoses at the firewall - as if you don't, you end up getting litres of water coming out of the matrix pipe!).
The bottom hose was actually quite difficult to get seated properly. It's a tight seal. But a bit of a wiggle, and it was all good.
So all back together properly, car up to temperature, and.... the moment we've all been waiting for...
HEAT!
Once I was certain everything was working nicely, I drained the water again, stuck in some G13, then refilled, etc.
Just had to replace the whole bloody interior now!
And now for the interesting bit of info for anyone wanting to tackle this themselves...
When refitting, I realised that I really didn't need to pull all that crap out to get to it. You can literally get it out by:
Draining coolant
Removing:
2x heater matrix hoses in the bulkhead
1x Torx screw on 'skirt' under the centre console
1x Torx screw on the lower pipe clip
1x Torx screw behind the glovebox (just flip it down as you would for a pollen filter change) to remove the air duct for more access room
2x Torx screws for the flap holding the matrix in place
And that is literally it! On reflection, I honestly believe the draining, removing/refitting of the matrix and filling back up with fluid could be done in under 2 hours. And that is by me - a ham-fisted DIY'er. How these garages have taken days and even weeks to do this job, is beyond me!
This was a few weeks ago now, and glad to report, it's working like a dream. It's maybe not 100%, but it's good enough for now. And it's a job I now know I can tackle easily, and quickly! Will probably give it another go, leaving the dishwasher tablet and boiling water in the matrix for longer next time.
Bodged up a little 'tool' to catch and drain the coolant from the matrix.
As you can see from the pic, the bottom hose is just held on by a pipe clip with a single screw. Took quite a decent tug to get the pipe free, but when it did, I was surprised how little fluid came out. Probably no more than a few hundred mls, but rather have it outside than underneath the carpet!.
The top hose is held in place by a simple clip which can just be pulled out. Again, the hose was in there pretty well. More tugging!
Once both hoses were off, there is a plastic cover over the matrix, held in by 2 torx bits. Once they are removed, the cover can be removed. Think it was hinged from the top.
Tada! Can finally see the matrix in all its glory.
With all that out of the way, the matrix just slides out nicely.
When the matrix was out, it looked pretty much brand spanking new, except for a few bent fins (probably from removal). Why wouldn't it, it lives out of sight its whole life. This alone would make me avoid buying a second hand heater matrix.
Anyway, I stuck a garden hose inside it (fits perfectly inside the ports) and noticed that the flow really was pretty poor. Gave it a good fews goes each way, but it was squirting more out of the side I was hosing it in from. Blowing through it like a cheap trumpet was tough on the lungs. Had read on the internet that people have had success with cleaning matrixes using dishwasher powder. I drained the matrix, crushed up a dishwasher tablet, then proceeded to fill the matrix with boiling water from the kettle. Took ages to fill from one side, which was expected given I knew it seemed clogged up. I made some makeshift bungs for each side using cling film and kitchen towels, one down each port. Then I was able to give it a good shake. Left it about an hour in total. Flushing it through afterwards, you could see the water was flowing much better now. And 'the trumpet test' (TM) certainly seemed a lot easier! :-D
Took it back outside and gave it a good few flushes each way with the garden hose. Definitely flowing better.
But there was loads of water stuck in the fins from all my hosepipe shenannigans. Didn't want to put the matrix back in like this, as all that would happen is this water would end up misting up my windows until it was all gone. So a little ingenuity...
Refitted the matrix, put the plastic cover back on - being careful to refit the rubber gasket, reattached the 2 screws holding the cover, refit the hoses and reattached the clips. Filled the header tank with water and started the engine to let it get up to temperature.
It was at this point, I noticed the lower matrix hose leaking!
No drama though, it was just not seated correctly. Drained the matrix again (make sure you remove the hoses at the firewall - as if you don't, you end up getting litres of water coming out of the matrix pipe!).
The bottom hose was actually quite difficult to get seated properly. It's a tight seal. But a bit of a wiggle, and it was all good.
So all back together properly, car up to temperature, and.... the moment we've all been waiting for...
HEAT!
Once I was certain everything was working nicely, I drained the water again, stuck in some G13, then refilled, etc.
Just had to replace the whole bloody interior now!
And now for the interesting bit of info for anyone wanting to tackle this themselves...
When refitting, I realised that I really didn't need to pull all that crap out to get to it. You can literally get it out by:
Draining coolant
Removing:
2x heater matrix hoses in the bulkhead
1x Torx screw on 'skirt' under the centre console
1x Torx screw on the lower pipe clip
1x Torx screw behind the glovebox (just flip it down as you would for a pollen filter change) to remove the air duct for more access room
2x Torx screws for the flap holding the matrix in place
And that is literally it! On reflection, I honestly believe the draining, removing/refitting of the matrix and filling back up with fluid could be done in under 2 hours. And that is by me - a ham-fisted DIY'er. How these garages have taken days and even weeks to do this job, is beyond me!
This was a few weeks ago now, and glad to report, it's working like a dream. It's maybe not 100%, but it's good enough for now. And it's a job I now know I can tackle easily, and quickly! Will probably give it another go, leaving the dishwasher tablet and boiling water in the matrix for longer next time.
A little update. The heating had been deteriorating recently. My dishwasher tablet cleanse had clearly not done the trick as well as I had thought. So, with winter ahead, and some long journeys planned over the next couple of months, I bit the bullet and ordered a new matrix and expansion tank. Don't have the time to fanny around these days.
Had hoped it would have arrived before the weekend, as was driving down to the Classic Car show, about 100 miles each way. Unfortunately didn't arrive.
Managed about 30 miles and noticed the air was blowing cool. Not ideal when ambient temps are <10°. But turns out that was the least of my worries, as the low coolant warning came on. Sure enough, when I got to the services, the coolant bottle was empty. One of the hoses on the bulkhead had popped off. It's been about 2 months since I had refitted it, so can only assume that pressure was building up due to the blocked matrix.
When the new matrix arrives, I'll do a proper 'how to' thread for the replacement. Will also get the stopwatch going too. ;-)
Had hoped it would have arrived before the weekend, as was driving down to the Classic Car show, about 100 miles each way. Unfortunately didn't arrive.
Managed about 30 miles and noticed the air was blowing cool. Not ideal when ambient temps are <10°. But turns out that was the least of my worries, as the low coolant warning came on. Sure enough, when I got to the services, the coolant bottle was empty. One of the hoses on the bulkhead had popped off. It's been about 2 months since I had refitted it, so can only assume that pressure was building up due to the blocked matrix.
When the new matrix arrives, I'll do a proper 'how to' thread for the replacement. Will also get the stopwatch going too. ;-)
Hi Scott,
Was wondering if you ever posted an update on how to replace the heater matrix start to finish (couldn't find another post?).
I've just found out that the reason for no hot air through my vents is a faulty heater matrix. Garage have quoted me £800 to fix. I've got a few days off and was thinking of replacing it myself, depending on how difficult a job it is.
Thanks,
C
Was wondering if you ever posted an update on how to replace the heater matrix start to finish (couldn't find another post?).
I've just found out that the reason for no hot air through my vents is a faulty heater matrix. Garage have quoted me £800 to fix. I've got a few days off and was thinking of replacing it myself, depending on how difficult a job it is.
Thanks,
C
An extract from ScottFR's post above (18/10/16)-
Refitted the matrix, put the plastic cover back on - being careful to refit the rubber gasket, reattached the 2 screws holding the cover, refit the hoses and reattached the clips. Filled the header tank with water and started the engine to let it get up to temperature.
It was at this point, I noticed the lower matrix hose leaking!
No drama though, it was just not seated correctly. Drained the matrix again (make sure you remove the hoses at the firewall - as if you don't, you end up getting litres of water coming out of the matrix pipe!).
The bottom hose was actually quite difficult to get seated properly. It's a tight seal. But a bit of a wiggle, and it was all good.
So all back together properly, car up to temperature, and.... the moment we've all been waiting for...
HEAT!
Once I was certain everything was working nicely, I drained the water again, stuck in some G13, then refilled, etc.
Just had to replace the whole bloody interior now!
And now for the interesting bit of info for anyone wanting to tackle this themselves...
When refitting, I realised that I really didn't need to pull all that crap out to get to it. You can literally get it out by:
Draining coolant
Removing:
2x heater matrix hoses in the bulkhead
1x Torx screw on 'skirt' under the centre console
1x Torx screw on the lower pipe clip
1x Torx screw behind the glovebox (just flip it down as you would for a pollen filter change) to remove the air duct for more access room
2x Torx screws for the flap holding the matrix in place
And that is literally it! On reflection, I honestly believe the draining, removing/refitting of the matrix and filling back up with fluid could be done in under 2 hours. And that is by me - a ham-fisted DIY'er. How these garages have taken days and even weeks to do this job, is beyond me!
This was a few weeks ago now, and glad to report, it's working like a dream. It's maybe not 100%, but it's good enough for now. And it's a job I now know I can tackle easily, and quickly! Will probably give it another go, leaving the dishwasher tablet and boiling water in the matrix for longer next time.
You can't miss them. Two big fat black hoses (one is Y-shaped), one above the other, directly behind the middle of the engine going straight into the firewall. You'll need a small pick/hook (or even just a very small screwdriver) to pull the spring retainers out a bit. They are the same sort of thing you get on the radiator hoses. Be careful not to pull the clips all the way off. I spent ages looking for one of mine!!
Once the spring retainer is pulled out, you just need to give the hoses a good pull, gently wiggling them a little as you do.
As mentioned, I used a wet vac to suck all the coolant out. Far less hassle and mess than draining from a lower radiator hose. I would recommend replacing all the coolant anyway, as that is no doubt filled with the crap that blocked the matrix in the first place. That reminds me... I did always mean to cut that old one open!
Defo an easy DIY job, and you can pick up new parts very reasonably.
Thanks for all the info Scott, what seemed to be a impossible task is actually now inviting.
I do however have a couple of questions.
1. I managed to get to one of the bottom connectors on the radiator to drain the coolant, this was a sh$tty job to note! Unfortunately I only managed to drain about 2 litres of coolant, I switched on the car briefly to see if the water pump will get some more out but had no luck. How do I completely drain the system?
2. Am I correct in saying the system self bleeds?
3. Got in under the dashboard as per your instruction and got to the matrix, don’t have a replacement yet but just wanted to give it a test run. My problem however is removing the two pipes in the engine bay that goes through the fire wall, do I just yank them out? Couldn’t see any clips?
4. The is a electrical sensor just in front of the heater matrix. How do you get this out? It has a little red tab that you pull back but after that this things still sticks like sh£t to a blanket?
My aim is to replace the matrix this coming weekend. I have tried to flush the system, the reservoir is full of gunk which tells me the garage who’s done the last service did something wrong.
Anyway thanks once again for shedding some light on this task.
I do however have a couple of questions.
1. I managed to get to one of the bottom connectors on the radiator to drain the coolant, this was a sh$tty job to note! Unfortunately I only managed to drain about 2 litres of coolant, I switched on the car briefly to see if the water pump will get some more out but had no luck. How do I completely drain the system?
2. Am I correct in saying the system self bleeds?
3. Got in under the dashboard as per your instruction and got to the matrix, don’t have a replacement yet but just wanted to give it a test run. My problem however is removing the two pipes in the engine bay that goes through the fire wall, do I just yank them out? Couldn’t see any clips?
4. The is a electrical sensor just in front of the heater matrix. How do you get this out? It has a little red tab that you pull back but after that this things still sticks like sh£t to a blanket?
My aim is to replace the matrix this coming weekend. I have tried to flush the system, the reservoir is full of gunk which tells me the garage who’s done the last service did something wrong.
Anyway thanks once again for shedding some light on this task.
1) These crazy modern engines have about 3 coolant circuits. The main engine circuit, the cooling circuit (ie: rads) and the charge cooler. All controlled by valves. This will be why you aren't getting much out. I'm sure there must be a method using VCDS to open some of these to drain more fluid into the radiator. You could just try filling it back up with water (or better still, some sort of coolant cleaner), run it up to temp so all circuits have it circulated, then drain again. Will take a few goes, but it will dilute the gunk.
2) Yes, system self bleeds
3) The 2 hoses behind the engine have spring clips(same as the rad hoses) which you need to pull. I use a small pick. Be careful, as you can easily drop these clips!
4) Can't remember any difficult connectors. There is most likely a small clip/button which needs to be pulled/pressed to release it. I always find pushing the plug in a bit helps ti release them before pulling it out.
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So the new heater matrix never turned up in time for the weekend however I decided I will take out the old one and try and see if I can unblock it somehow.
Followed the instructions from Scott and I got it out in 45min with draining the coolant. The only other thing I had to do is remove the blower as this stopped the matrix from coming out. BOOM! Felt like I won the lottery. So to my shock the matrix had some kind of jelly substance in the bottom port.?????
Tried blowing through the matrix and it was definitely blocked! So I filled the matrix with some vinigar and placed the whole thing in a pot and brought it to boil. The stuff that came out was crazy. Rusty sand and more of this jelly substance. Then rinsed it with the hose and suddenly the water was running freely. GREAT!!!! Put everything back together which took no time and filled her up. I now have heating again! Super glad.
One question is does anyone know why I would have the jelly substance in there? Car has full service history with Seat and I had the car from new so the only people who ever worked in the coolant was the service centre. Can this be from using different grades perhaps?
Followed the instructions from Scott and I got it out in 45min with draining the coolant. The only other thing I had to do is remove the blower as this stopped the matrix from coming out. BOOM! Felt like I won the lottery. So to my shock the matrix had some kind of jelly substance in the bottom port.?????
Tried blowing through the matrix and it was definitely blocked! So I filled the matrix with some vinigar and placed the whole thing in a pot and brought it to boil. The stuff that came out was crazy. Rusty sand and more of this jelly substance. Then rinsed it with the hose and suddenly the water was running freely. GREAT!!!! Put everything back together which took no time and filled her up. I now have heating again! Super glad.
One question is does anyone know why I would have the jelly substance in there? Car has full service history with Seat and I had the car from new so the only people who ever worked in the coolant was the service centre. Can this be from using different grades perhaps?
That sounds very much like the wrong grade of coolant has been used at some point.
I think there must be a fault with the engine design, as the coolant I took out of mine originally was absolutely minging. Had a bonfire sort of smell.
Just found an old photo from when I drained it. Gross!
Mine was also full Seat history up to that point (about 75k I think).
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Just found an old photo from when I drained it. Gross!
Mine was also full Seat history up to that point (about 75k I think).
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And for those interested, I cut the old matrix open after is replaced it because it blocked up again a few months after my initial cleaning.
You can see some sand like deposits in the veins which restricts flow. Maybe cat litter.
My guess is these blockages go the whole way through the matrix, and because the veins are so tiny, probably the narrowest part of the entire coolant system, they are prone to catching any crud floating around.
Think it's over a year since I fitted the new matrix. The coolant is still bright pink, although I did notice recently that the burnt smell is starting to make a reappearance.
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You can see some sand like deposits in the veins which restricts flow. Maybe cat litter.
My guess is these blockages go the whole way through the matrix, and because the veins are so tiny, probably the narrowest part of the entire coolant system, they are prone to catching any crud floating around.
Think it's over a year since I fitted the new matrix. The coolant is still bright pink, although I did notice recently that the burnt smell is starting to make a reappearance.
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