[SwissJetPilot]

Some additional info on heater cores from Charles the Humble Mechanic -

After you do the first flush of the core and get the bulk of whatever debris is in there out, you can pour this in, and let it sit for while, and then flush it again. It's designed to flush the entire system, but you can use it to just clean the core too.

 

[Arnedk]

Thanks again guys @jakob_b @SwissJetPilot

My garden hose doesn't even remotely reach the car parking, so that wasn't an option. I instead just used warm water and some cooling system flush to get out debris, blowing it out (and letting the flush sit for 10 min) eventually it was all clear. A lot came out, bits of sandy looking nonsense and what not. About the same or a bit more as I've seen in the videos I've watched.

I then refilled with coolant mix, reconnected the pipes (which were actually bloody hard to get on) and started the car, topping up coolant with the cap open. I then took the car for a 15 minute relateively spirited drive, but in the end, maybe it's 3 degrees warmer at best...

Edit: perhaps bleeding the core is needed, as all i did was fill it with liquid but I'm thinking that was perhaps not good enough.It's dark here now so that's a job for tomorrow. Is there a bleeder hole on the top pipe? I didn't notice it today.

 

[jakob_b]

Thanks again guys @jakob_b @SwissJetPilot

My garden hose doesn't even remotely reach the car parking, so that wasn't an option. I instead just used warm water and some cooling system flush to get out debris, blowing it out (and letting the flush sit for 10 min) eventually it was all clear. A lot came out, bits of sandy looking nonsense and what not. About the same or a bit more as I've seen in the videos I've watched.

I then refilled with coolant mix, reconnected the pipes (which were actually bloody hard to get on) and started the car, topping up coolant with the cap open. I then took the car for a 15 minute relateively spirited drive, but in the end, maybe it's 3 degrees warmer at best...

Edit: perhaps bleeding the core is needed, as all i did was fill it with liquid but I'm thinking that was perhaps not good enough.It's dark here now so that's a job for tomorrow. Is there a bleeder hole on the top pipe? I didn't notice it today.

Yeah that’s what I tried as the very first thing and I had the same issue where it wasn’t much warmer but after a flush with some cleaner it should be better

 

[jakob_b]

Yeah that’s what I tried as the very first thing and I had the same issue where it wasn’t much warmer but after a flush with some cleaner it should be better

And no I do not believe there is a bleeder atleast I didn’t use one

 

[SwissJetPilot]

Did you try flushing in both directions...?

 

[Arnedk]

Did you try flushing in both directions...?

Yep I did...

 

[Arnedk]

Yeah that’s what I tried as the very first thing and I had the same issue where it wasn’t much warmer but after a flush with some cleaner it should be better

Maybe I should go visit family who have an accessible hose and try again....

 

[jakob_b]

Maybe I should go visit family who have an accessible hose and try again....

Yeah, if you have any friends or family with hoses, but make sure if you do it again to use some kind of flushes like the Prestone mix or the Thoroflush powder when you are flushing the heater matrix.

 

[SwissJetPilot]

@ Arnedk - If and when you flush the core again, can you take some pictures of the process and post them here in the Forum? it would be interesting for anyone else that wants to do this so they can see what's involved.

 

[jakob_b]

@ Arnedk - If and when you flush the core again, can you take some pictures of the process and post them here in the Forum? it would be interesting for anyone else that wants to do this so they can see what's involved.

If it helps I have some photos

 

[SwissJetPilot]

@ jakob_b - Thanks! Actually if you had some closer shots of removing the connectors and how you put on the clear flush lines, that would be really helpful.

Are the connectors difficult to remove...?

It looks pretty straight forward, just use a screwdriver to lift the metal retaining clip to release it...?

I researched the actual parts to get a better understanding of what you guys are working with. And from the photos shown below I noticed both the male and female connectors are keyed, meaning one should not attempt to rotate it.

Both the upper and lower connectors just pull straight off. Is this also correct...?

 

[Arnedk]

Are the connectors difficult to remove...? It looks pretty straight forward, just use a screwdriver to lift the retaining clip to release it...?

I also noticed it is keyed, meaning one should not attempt to rotate it. It just pulls straight off. Is this correct?

View attachment 511734
View attachment 511738

That's how one would assume they work but even after the clip is in the open position, pulling the actual thing off (straight) takes a lot of effort. Then getting it back on is the same story. Not sure if I'm doing it wrong. Perhaps @jakob_b can comment on his experience.

 

[Arnedk]

@SwissJetPilot @jakob_b

I've re-done the job today with the help of my friendly neighbors again. Bought a hosepipe and blasted it both ways, had product in there for a good 15-20 minutes, moving it back and fourth in the system for some time. In the end, mostly it seems in vain, as the heater is again 5 degrees warmer than it was before, or maybe less. We took a few photos but they're on my phone - I'll add them later. For now I'm a bit miserable that despite all the effort and expense, the car is uncured...

Could it be the thermostat? Or some other part? If so, why wouldn't it flag up an error code?

A mechanic suggested I leave the coolant cap off tonight, but I think the system is self clearing for any airlocks anyway, right? Or should I do it still?

Anyway

 

[Arnedk]

I've watched the below video to understand where to feel for something heating up. Maybe a good test for the thermostat.

 

[jakob_b]

@ jakob_b - Thanks! Actually if you had some closer shots of removing the connectors and how you put on the clear flush lines, that would be really helpful.

Are the connectors difficult to remove...?

It looks pretty straight forward, just use a screwdriver to lift the metal retaining clip to release it...?

I researched the actual parts to get a better understanding of what you guys are working with. And from the photos shown below I noticed both the male and female connectors are keyed, meaning one should not attempt to rotate it.

Both the upper and lower connectors just pull straight off. Is this also correct...?

View attachment 511740

Hi apologies for the late response sadly I don't have any closer-up shots, but the connectors are really easy to remove, just the c clamps, I just used a flat head, and once they are off, you just pull, and they come off I was super rough with mine so you should be fine just don't lose the c clips

 

[jakob_b]

@SwissJetPilot @jakob_b

I've re-done the job today with the help of my friendly neighbors again. Bought a hosepipe and blasted it both ways, had product in there for a good 15-20 minutes, moving it back and fourth in the system for some time. In the end, mostly it seems in vain, as the heater is again 5 degrees warmer than it was before, or maybe less. We took a few photos but they're on my phone - I'll add them later. For now I'm a bit miserable that despite all the effort and expense, the car is uncured...

Could it be the thermostat? Or some other part? If so, why wouldn't it flag up an error code?

A mechanic suggested I leave the coolant cap off tonight, but I think the system is self clearing for any airlocks anyway, right? Or should I do it still?

Anyway

sorry to hear that your car only a lil warmer I imagine your heater core is just extremely gunked up or something like that my heat in my car isn't amazing for sure and I've heard around that tt's and golfs kinda suffer from lack of heat from the factory sometimes but idk it works for my Canadian climate and mine sure got hotter than that when I did my flush so I would maybe consult a mechanic at this point ask if there's any more you can do. but if you wanna try again maybe just continue flushing it until everything is removed i did mine like 4 times before everything was removed but it does totally get annoying having to take the intake pipes off and such over and over again.

 

[jakob_b]

@SwissJetPilot @jakob_b

I've re-done the job today with the help of my friendly neighbors again. Bought a hosepipe and blasted it both ways, had product in there for a good 15-20 minutes, moving it back and fourth in the system for some time. In the end, mostly it seems in vain, as the heater is again 5 degrees warmer than it was before, or maybe less. We took a few photos but they're on my phone - I'll add them later. For now I'm a bit miserable that despite all the effort and expense, the car is uncured...

Could it be the thermostat? Or some other part? If so, why wouldn't it flag up an error code?

A mechanic suggested I leave the coolant cap off tonight, but I think the system is self clearing for any airlocks anyway, right? Or should I do it still?

Anyway

sorry to hear your cars only slightly warmer my car definitely doesn't have he greatest heating and I've heard from others that some of those cars and golfs suffer the same crappy heating from the factory but mine got much warmer when I did my original flush but I did do mine like 4 times in total tho, I used almost an entire bottle of thoroflush and by the end there was still tiny particles coming out so It very well could be that there still is build up from old coolant in the heater core at least

sorry to hear that your car only a lil warmer I imagine your heater core is just extremely gunked up or something like that my heat in my car isn't amazing for sure and I've heard around that tt's and golfs kinda suffer from lack of heat from the factory sometimes but idk it works for my Canadian climate and mine sure got hotter than that when I did my flush so I would maybe consult a mechanic at this point ask if there's any more you can do. but if you wanna try again maybe just continue flushing it until everything is removed i did mine like 4 times before everything was removed but it does totally get annoying having to take the intake pipes off and such over and over again.

that's about all I could imagine I really don't think you would replace your matrix unless its like actually damaged which at that point it would be noticeable in that your car would probably smell like coolant in the cab, I've also seen something about a silica bag Audi used to put in some of their cars in the actual coolant ball to expand the "coolant life 🤪" idk if it applies to the later gen mk2 tts because my car didn't have it but apparently that can release silica into the coolant system which damages the heater core and water pump and can also make the heat really weak but that's more obvious in that your cars also overheating so maybe look into that tho probably isn't the case here but just pointing it out. also just wondering how much gunk came out on your flush? because I had like probably an oil drain pan worth of just old build-up on the fins in the matrix id just say keep on flushin

 

[SwissJetPilot]

I guess the next question would be are you getting a good flow through the heater core?

If not, then it's probably really blocked and requires some additional attempts.

If you haven't done so already, it might be worth blowing out all the coolant that's in it so it's completely void of any coolant, and then fill it with the coolant flush/cleaner solution and let it sit for 30 minutes or so and then flush it again.

While it is possible to DIY a heater core replacement, it does not look easy, at least from the YouTube videos I have reviewed. Personally, I would make every possible effort to verify the core is actually clear before going that route.

However if flow is good, then it might be something else like the thermostat.

 

[Arnedk]

I guess the next question would be are you getting a good flow through the heater core?

If not, then it's probably really blocked and requires some additional attempts.

If you haven't done so already, it might be worth blowing out all the coolant that's in it so it's completely void of any coolant, and then fill it with the coolant flush/cleaner solution and let it sit for 30 minutes or so and then flush it again.

While it is possible to DIY a heater core replacement, it does not look easy, at least from the YouTube videos I have reviewed. Personally, I would make every possible effort to verify the core is actually clear before going that route.

However if flow is good, then it might be something else like the thermostat.

The flow is not bad. It's not exactly super smooth blowing coolant/air through it, but the pipes which were attached were not ideal and had some kinks in it, so that's probably the kickback I felt. Honestly though it felt like it was quite smooth running. Would water need to go through the whole rad to flow, or could it be that it's flowing well only through part of the rad?

I did leave the cleaner inside for 15 min the day before yesterday, and then yesterday again.

Thoroflush is hard to get in the UK, so I used what's in the auto shop. These two: Holts Speedflush 250ml | Halfords UK and Wynns Radiator Flush | Halfords UK - maybe they are crap products, but they've got good reviews on Amazon.

 

[jakob_b]

The flow is not bad. It's not exactly super smooth blowing coolant/air through it, but the pipes which were attached were not ideal and had some kinks in it, so that's probably the kickback I felt. Honestly though it felt like it was quite smooth running. Would water need to go through the whole rad to flow, or could it be that it's flowing well only through part of the rad?

sorry do you mean the whole rad or matrix?

I'm also sure the products were totally fine for the application, mine was just recommended by a mechanic shop nearby.