Coolant blown out from expansion bottle

Macrezz

New member
Joined
Aug 20, 2020
Location
Ireland
TDI
2.0l TDI 184
Hello everyone. I am another follower of this thread. Similar story to you all. I am about to start changing the expensive stuff and was hoping some of you might be able to sharpen the direction in which I should start.

My situation.
Car is Seat Leon mk3 2 liter TDI 184
Dual zone climate control.
I changed the bottle cap then the bottle before looking for more information and finding this place.
Little heat out of the vents when the car is hot and the heating is on max. I'm in Ireland. Righthand drive. The far right vent emits the most heat. Tapers off quickly between the other three, running right to left.
Coolant bottle expels it's contents now and then. Probably during dpf regen. I can't say for sure though. If I stop the car and it goes into active regen, I pop the bonnet and release the pressure in the expansion tank. That tends to help coolant loss.
Oil temperature reached 104c this morning on my 25min drive to work. I dove easy but in 3rd gear, keeping the revs around 3k.
Manual says normal temps are 80 to 120c.

After reading here I took my car to get the heating matrix back flushed. My mechanic said he got a strong flow and didn't think there was anything wrong with it.
The other day he contacted Seat. They mentioned the heating matrix and he told them what he thought of the condition of mine. So they told him to change the two circulation pumps. Both costing around €215. They are slightly different pumps.
I don't mind changing both of them but would rather not waste €215 if I don't need to.

Does anyone have any advice?
Is the next step to change both pumps?
Should I change the pump that feeds the heating matrix first and see how it works out?
Or should I be looking elsewhere?

Any help would be greatly appreciated.
Thanks.
 
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nathanso

Well-known member
Joined
Mar 31, 2019
Location
Redwood City, CA
TDI
2015 GSW TDI S 6M
Is there preventative maintenance that might serve to avoid this ugly scenario? Early coolant change? Aftermarket water pump?? I've already swapped out my coolant reservoir so I have the updated, non-perforated silikat pouch but I suspect that's not going to help much if this issue strikes my TDI. I was watching a youtube video on the water pump (
watch at minute 27) and a sticking pump impeller disabler might explain these coolant reservoir blow-out symptoms. I've read VW is dealing with a class action on a different engine's failed water pump so maybe this is similar/common?

EDIT: Just seeing Kamilecki166's post from earlier in this thread reporting the same thing. I'm going to look into swapping out my wp.
 
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Macrezz

New member
Joined
Aug 20, 2020
Location
Ireland
TDI
2.0l TDI 184
Is there preventative maintenance that might serve to avoid this ugly scenario? Early coolant change? Aftermarket water pump?? I've already swapped out my coolant reservoir so I have the updated, non-perforated silikat pouch but I suspect that's not going to help much if this issue strikes my TDI. I was watching a youtube video on the water pump (
watch at minute 27) and a sticking pump impeller disabler might explain these coolant reservoir blow-out symptoms. I've read VW is dealing with a class action on a different engine's failed water pump so maybe this is similar/common?

EDIT: Just seeing Kamilecki166's post from earlier in this thread reporting the same thing. I'm going to look into swapping out my wp.
Hi. Just wondering what your situation is? Car/Engine, mileage & symptoms?

I was just onto Seat in the hope for a little more information about which direction to go but nothing unfortunately. Could be the matrix, either two circulation pumps & now you highlighted the water pump.

Edit.
Checked my milage. I'm at 117,000km. Timing belt change is 210,000 or five years, car is 2013 so I'm due a change. At least that is a constructive thing to try, so I'm going to sort that with the water pump, then see where I am.
 
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shocks

Active member
Joined
Jan 22, 2020
Location
Perth AU
TDI
Golf MK6 2.0TDI (103KW CFFB) Comfortline, Golf MK7 2.0TDI Highline (CRBC 110KW), Passat Alltrack Wolfsburg Ed. 2.0TDI (DFHA 140KW)
Hi. Just wondering what your situation is? Car/Engine, mileage & symptoms?

I was just onto Seat in the hope for a little more information about which direction to go but nothing unfortunately. Could be the matrix, either two circulation pumps & now you highlighted the water pump.

Edit.
Checked my milage. I'm at 117,000km. Timing belt change is 210,000 or five years, car is 2013 so I'm due a change. At least that is a constructive thing to try, so I'm going to sort that with the water pump, then see where I am.
Macrezz, I wouldn't go too far down the rabbit hole on the water pump being the issue. I was losing coolant from my bottle and I had exhaust gases in my coolant so I concluded the two were connected. I thought my water pump was the smoking gun ... but after replacing this and the head gasket I lost coolant on my very first drive to work. Like so many other people here with this issue, it was simply a case of a small amount of buildup in the heater matrix coupled with the heat from the EGR valve reopening after DPF regen (and a clear design flaw in VW's cooling system). I replaced my heater matrix and I haven't lost a drop of coolant after 14,000 kms.

The pump did possibly cause the other issue of exhaust gas in my coolant as I can't detect it anymore after changing the head gasket and pump, who knows though. Heater Matrix should be the first and one of the cheapest repairs you try in my opinion. You can even do it your self, it's particularly easy on a RHD vehicle.
 

nathanso

Well-known member
Joined
Mar 31, 2019
Location
Redwood City, CA
TDI
2015 GSW TDI S 6M
My solution for preemptively avoiding the jammed water pump impeller shroud issue and the resulting damage a sealed-system overheat could cause was to disconnect the water pump solenoid and connect the wiring harness to a new, second solenoid that I purchased for this purpose. Thus far, over a half-dozen trips and several hundred miles, my ECT has remained in the 192-197F range (according to my ODB2 scanner) and no error codes have been thrown.

 

Macrezz

New member
Joined
Aug 20, 2020
Location
Ireland
TDI
2.0l TDI 184
Macrezz, I wouldn't go too far down the rabbit hole on the water pump being the issue. I was losing coolant from my bottle and I had exhaust gases in my coolant so I concluded the two were connected. I thought my water pump was the smoking gun ... but after replacing this and the head gasket I lost coolant on my very first drive to work. Like so many other people here with this issue, it was simply a case of a small amount of buildup in the heater matrix coupled with the heat from the EGR valve reopening after DPF regen (and a clear design flaw in VW's cooling system). I replaced my heater matrix and I haven't lost a drop of coolant after 14,000 kms.

The pump did possibly cause the other issue of exhaust gas in my coolant as I can't detect it anymore after changing the head gasket and pump, who knows though. Heater Matrix should be the first and one of the cheapest repairs you try in my opinion. You can even do it your self, it's particularly easy on a RHD vehicle.
Thanks for your reply.
Maybe you are right. I'm caught between what to change next. Seat have suggested I go in for a diagnostic test to find out what's wrong. I asked them twice if the test would tell me if there is a problem with circulation pumps or the matrix. They evaded the question both times. I feel like the test will be a waste of €90.
I was all set to change the matrix at the start of the year. That changed when my mechanic said he got a good flow through it. I haven't been able to make a decision since.
I wouldn't have a clue of how to change the matrix myself. Is there a video guide by any chance? I'll pawn it off to an expert if it looks to much for me.
Thanks again.
 

shocks

Active member
Joined
Jan 22, 2020
Location
Perth AU
TDI
Golf MK6 2.0TDI (103KW CFFB) Comfortline, Golf MK7 2.0TDI Highline (CRBC 110KW), Passat Alltrack Wolfsburg Ed. 2.0TDI (DFHA 140KW)
I wouldn't have a clue of how to change the matrix myself. Is there a video guide by any chance? I'll pawn it off to an expert if it looks to much for me.
Thanks again.
looks like someone made a video here ...

If you have no experience working on engines then maybe avoid this one, I would describe it as a little bit harder than an oil change and you'll need an air compressor to blow the matrix clear of coolant before disconnecting all the coolant pipes or you'll have a mess in your cabin. The procedure in the service manual covers everything in detail, you can get these manuals from the Erwin Volkswagen website for a fee (it's time based but you can just buy 1 hour and download all the manuals at once for your car).

I wouldn't pay the 90 euro for the test, the whole job is probably a 300-400 euro job including parts and labour. Less than 200 if you do it yourself.
 

Macrezz

New member
Joined
Aug 20, 2020
Location
Ireland
TDI
2.0l TDI 184
Th
looks like someone made a video here ...

If you have no experience working on engines then maybe avoid this one, I would describe it as a little bit harder than an oil change and you'll need an air compressor to blow the matrix clear of coolant before disconnecting all the coolant pipes or you'll have a mess in your cabin. The procedure in the service manual covers everything in detail, you can get these manuals from the Erwin Volkswagen website for a fee (it's time based but you can just buy 1 hour and download all the manuals at once for your car).

I wouldn't pay the 90 euro for the test, the whole job is probably a 300-400 euro job including parts and labour. Less than 200 if you do it yourself.
Thanks again.
Really appreciate it.
 

Gavk

New member
Joined
Oct 18, 2020
Location
Irepand
TDI
2.0 tdi fr
Hi all, I have a 14 leon fr 184 BHP. I have just replaced my heater matrix 2 weeks ago as I was having the same symptoms as a lot on here, coolant blowout from cap, no heat coming through the vents pressure tested and gas tested all was good.Since I replaced the heater the heat has came back, great. But I checked the coolant there today for the first time since I got the heater replaced and the coolant was just in the middle between max and min, when it was replaced it was at max,
My question is should the coolant have to be topped up again? I have drove the car about 200 miles since I got it back and stopped it up once with about 200ml coolant
 

MaximisDoom

New member
Joined
Oct 18, 2020
Location
Nottingham UK
TDI
2.0 184
I had the same issue with a coolant blow out and then a subsequent loss heat in the cabin. The heater gets fairly warm but not hot when blower on low and driving round town but on a long run, speeds over 40 - 70 mph the heater goes cold. Or if the blower is turn up to half way or above the heater goes cold. I have replaced the main water pump with cam belt change and also replace the secondary pump due to a warning light saying the secondary pump was not functioning and I still have exactly the same problem. Only thing left to do is try the heater matrix. Are there any coolant flow control solenoids etc on the heater matrix part of the circuit as SEAT are totally unhelpful as usual? I will post back if I ever manage to get this sorted!
 

MaximisDoom

New member
Joined
Oct 18, 2020
Location
Nottingham UK
TDI
2.0 184
Hi all, I have a 14 leon fr 184 BHP. I have just replaced my heater matrix 2 weeks ago as I was having the same symptoms as a lot on here, coolant blowout from cap, no heat coming through the vents pressure tested and gas tested all was good.Since I replaced the heater the heat has came back, great. But I checked the coolant there today for the first time since I got the heater replaced and the coolant was just in the middle between max and min, when it was replaced it was at max,
My question is should the coolant have to be topped up again? I have drove the car about 200 miles since I got it back and stopped it up once with about 200ml coolant
I'd say that amount of water displacement is totally normal as some air could have circulated through the system, hence the water in the bottle replacing said air. I'd give it a good run and check again as when I had both pumps changed it took a couple of top ups in mine before the level stayed consistantly at the same level.
 

Gavk

New member
Joined
Oct 18, 2020
Location
Irepand
TDI
2.0 tdi fr
I'd say that amount of water displacement is totally normal as some air could have circulated through the system, hence the water in the bottle replacing said air. I'd give it a good run and check again as when I had both pumps changed it took a couple of top ups in mine before the level stayed consistantly at the same level.
Thanks for the info maximisdoom I was thinking the same about the air.hopefully it will sort it self out and find its level, dont want replacing more parts. Car is running fine since the new matrix no blow out when regen or on long drive, where as before after a regen or long drive the coolant would be empty
 

Dandan62

New member
Joined
Nov 10, 2020
Location
Sussex
TDI
Seat lein
Just to add to this common issue I had the same symptoms of losing coolant through the expansion tank. The silicone balls had gone from the tank and I had no hot air. It took 3 system flushes, replacement matrix and new coolant tank but all is fine now. I luckily have a model where with practice the matrix can be removed in 20 minutes! I will be doing a yearly flush and keeping an eye on the silicone balls from now on!
 

Wiseman22

New member
Joined
Nov 28, 2020
Location
Bucharest
TDI
Golf mk7 variant 2.0 TDI 150HP
Hej guys, I am new here and can share my same experience with a Golf mk7 variant 2.0 tdi 150 hp, 120,000 km.
March 2020 - loosing coolant heavily and heating wasnt working at all and had smell of exhaust gasses in the coolant tank. Service said there is some kind of residue in the coolant (they blame the coolant but i use G7 original wv only). Water pump was blocked so i replaced it and for heating they washed the matrix and started working again (didnt work as it shouls but i would only figure it out way later) .
Sep 2020 - 4000 km after, didnt use heating all summer. Heating disnt work well when i tried. Started loosing more and more coolant again, it never stooped completley actually. Service found pump blocked again and said i am loosing coolant through the gas cooler + EGR unit which gives the bad smell in the coolant tank because it looses gases in system.After changing EGR and pump again, they washed again the heater but the heat was not working as it should. So then they said that the matrix heater was still clogged even after washing for 2 days with the special liquid.
After i changed the matrix, my heating is burning my hand and disnt loose coolant for 1000 km even reved up.
Dont be scared if after changing matrix you lose some coolant, the system is clearing the air inside and you have to fill in when engine is cold (in my case i added up to 500ml) but not a drop since last refil.

I am sure the matrix was clogged and that solved it but i am not 100% about the EGR loosing coolant and giving the smell. I didnt fimd anybody who can test the bad part yet.

As previously mentioned i also recommend you start with the cheapest - matrix heater and after that see if you still have issues.
 

dtrvler

Veteran Member
Joined
Jul 21, 2017
Location
Las Vegas
TDI
2006 Jetta TDI 5 spd
Boiling coolant out of the overflow means bad oring on coolant bottle or other lack of seal in cooling system. It needs to be under pressure. Pressure test cooling system.
Bubbles in the cooling system is often misdiagnosed as combustion pressure leaking into cooling system.
 

Kel8117

Member
Joined
Feb 8, 2021
Location
UK
TDI
VW Golf MK7 GT TDI
Hey all. Golf Mk7 TDI 2013 recently showing many of the same symptoms identified here, occasionally spilling coolant out from the overflow in expansion tank, seemingly following DPF regen. This thread has been brilliant as I immediately thought it was either a faulty expansion tank/cap or both, or the more likely the dreaded head gasket.

Pleased that many managed to narrow the issue down to the heater matrix and replaced which seemed to fix the issue. I’d be really interested to hear how that is going for those that it worked for, but equally what other ongoing issues people have experienced after changing the matrix and if they thought it was compounded by the issue or just coincidence?

also a little advice, I’m driving it 700 miles in a few weeks, I’m currently in Gibraltar, moving back to uk and the journey is 700miles - really reluctant to let the locals here investigate or start to work on it (haven’t had great experiences in the past,+ they are really expensive and the communication barrier could be troublesome!). Any concerns or advice for that length of journey with the present issues?
 

Dandan62

New member
Joined
Nov 10, 2020
Location
Sussex
TDI
Seat lein
Hi. I had all the same symptoms. Losing water from the expansion tank and no heat from the vents. The silicone bags in the tank had gone so I presume this is what gets into the system and blocks the matrix. I changed it once which improved it for a while. Same problem returned so I put the original matrix back it which I had flushed. It was definitely blocked. It is an easy think to get at in my Leon. Since then, about 5k miles, it has been fine. Full heat from vents and not a drop of coolant gone.
When I had the issue I was still driving it about 500 miles a week. I kept a large amount of coolant with me and watched the level. I watched the oil temp as the coolant temperature never went above 90. If the oil temp went above about 115 I probably needed to stop and check. I worked out it happened about every 300 miles which I believe may be the regen interval. Hope that helps.
 

shocks

Active member
Joined
Jan 22, 2020
Location
Perth AU
TDI
Golf MK6 2.0TDI (103KW CFFB) Comfortline, Golf MK7 2.0TDI Highline (CRBC 110KW), Passat Alltrack Wolfsburg Ed. 2.0TDI (DFHA 140KW)
I've completed just over 23K since changing my heater matrix out and I've only had to top up with about 200ml of coolant when I did a service at about 18K after the change out. Some coolant loss seems to be "normal" with the tdi's from my experience owning four of them now.

Any concerns or advice for that length of journey with the present issues?
If you're taking the chance driving that 700km, you'll probably need to take at least 1 litre of premixed G13 coolant with you to keep it topped up after each DPF regen cycle. I was losing between 200-300ml each time the spew happened. It's up to you based on how risk tolerant you are, but 700kms doesn't sound too bad to me, I was driving around for a few weeks before I sorted mine out. Just stop and top up every time you get a low coolant warning.
 
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Kel8117

Member
Joined
Feb 8, 2021
Location
UK
TDI
VW Golf MK7 GT TDI
Thanks for the speedy reply guys, much appreciated! I’m stuck between a rock and a hard place, I need to get me and the car to my uk destination upon which I will get the heater matrix changed as the first opportunity.
Out of interest, would it be worth flushing the heater matrix through, prior to the journey, in hope that it would buy me a few more miles - is that even possible or is this only achievable by removing it part itself (in which case you might as well replace). I ask as I do plan to have the oil changed prior to me leaving. I do trust them to do that and I could maybe ask for them to do a flush at the same time? I should also mention it is 700miles so approx 1100k of that would make a difference to your initial advice? I will be splitting the journey over 2 days.
 

shocks

Active member
Joined
Jan 22, 2020
Location
Perth AU
TDI
Golf MK6 2.0TDI (103KW CFFB) Comfortline, Golf MK7 2.0TDI Highline (CRBC 110KW), Passat Alltrack Wolfsburg Ed. 2.0TDI (DFHA 140KW)
My Golf is doing a regen about every 300kms or so from memory, so a 1 litre bottle of G13 Coolant mixed 50/50 will be more than enough for a 1100km journey.

You can flush the matrix via the two pipes connecting it to the rest of the coolant system on the engine side of the firewall but some people on here haven't had great luck with flushing. I wouldn't bother wasting time with the flush, the heater matrix is such a simple job (at least in a RHD Golf) you might as well spend your time or money on that, maybe even before your journey.
 

MaximisDoom

New member
Joined
Oct 18, 2020
Location
Nottingham UK
TDI
2.0 184
I had the same issue with a coolant blow out and then a subsequent loss heat in the cabin. The heater gets fairly warm but not hot when blower on low and driving round town but on a long run, speeds over 40 - 70 mph the heater goes cold. Or if the blower is turn up to half way or above the heater goes cold. I have replaced the main water pump with cam belt change and also replace the secondary pump due to a warning light saying the secondary pump was not functioning and I still have exactly the same problem. Only thing left to do is try the heater matrix. Are there any coolant flow control solenoids etc on the heater matrix part of the circuit as SEAT are totally unhelpful as usual? I will post back if I ever manage to get this sorted!
I have recently had to get a new car due to the issues described in this thread and quoted above. Everything started with a water blow out, changed both pumps etc. then took to a VAG group specialist. At first he said it could be the EGR valve, an oil cooler seal, heater matrix etc etc. He then did a head gasket test....... Head has gone!! Unbelievable. I have had this car from new, never had an over heat issue, always driven in a regular manner and only 80,000 miles! The guy said he's NEVER seen one go that early. Just sh*t luck I guess. It can be repaired but not by them, even though they are a specialist due to the nature of the tooling required to put the engine back together after removing the head, some gearing and positioning inside the block. Apparently the manufacturer will only allow dealers to hold the specialist tool. You can't even hire them. Repair via the specialist including the cost of a recovery car engine (easier to buy a used engine and fit rather than fix the broken head) £4,000 ish! Dealer price to fix the broken head £8,000 - £10,000! And hence the new car! So, my advice is rather than trying other methods to fix this issue please have a head gasket test done first before buying or paying for anything else as this will be a complete waste of money, as in my case, if the head has gone!
 

shocks

Active member
Joined
Jan 22, 2020
Location
Perth AU
TDI
Golf MK6 2.0TDI (103KW CFFB) Comfortline, Golf MK7 2.0TDI Highline (CRBC 110KW), Passat Alltrack Wolfsburg Ed. 2.0TDI (DFHA 140KW)
MaximusDoom, I would strongly advise you to find a new mechanic. The magic tools he's referring to cost about a hundred quid and even though doing a head gasket repair is time consuming, it should be well within the ability of anyone claiming to be a mechanic. Any independent specialist VAG mechanic should be able to do any VAG repair without exception, even adaptations requiring factory authorizations.

I also wouldn't advise anyone to start with the assumption it's a blown head gasket. The very large majority of people on this forum have fixed their issues with a heater matrix change and this in my opinion should be the starting point for most people in the affected mileage/age range we have seen.

What sort of head gasket test did this "mechanic" do, a gas test isn't conclusive as I found out when I decided to change my head gasket out based on results of one of these tests. I did this head gasket replacement by myself by the way, and without having burglarize a dealership for tools as well mind. I found nothing wrong with the head gasket.

Unfortunately, I didn't discover this helpful thread until I was halfway through that exercise, after putting everything back together I was still getting blowouts of coolant. Once I changed that Matrix though, voilà, problem gone!
 

dtrvler

Veteran Member
Joined
Jul 21, 2017
Location
Las Vegas
TDI
2006 Jetta TDI 5 spd
Try coolant cap oring. Even some new ones wont hold pressure bc they are undersized. Put a thicker one in if you have to.
I have seen vw diesels boil coolant out the coolant cap past the oring. Happens under load like mountain climbing. Such a small item, easy to overlook. System needs to develop pressure to work properly. This is often misdiagnosed as head gasket.
 

shocks

Active member
Joined
Jan 22, 2020
Location
Perth AU
TDI
Golf MK6 2.0TDI (103KW CFFB) Comfortline, Golf MK7 2.0TDI Highline (CRBC 110KW), Passat Alltrack Wolfsburg Ed. 2.0TDI (DFHA 140KW)
In my case I did a lot of things before I got to the head gasket (and before I found the info in this thread regarding the matrix). I did a coolant system pressure test (passed), and as I didn't have the adaptor to pressure test the relief valve cap, I replaced the cap entirely to rule out the o-ring and relief valve. I then did a gas test which strongly indicated the presence of exhaust gas in the coolant system.

I think having some or all of the following items should lead to a reasonable suspicion that the Matrix is to blame and not something more serious:

1) The vehicle is 7 - 8 years old
2) The vehicle has done >100,000kms
3) The coolant is being ejected from the bottle, not just lost.
4) The coolant loss is happening regularly (300-400 kms intervals when the DFP regen cycle occurs)
5) Sometimes, there is a measurable difference (using a IR thermometer, not just your hand) between the heat coming from the front vents

As for the gas test, as I mention in my very early posts, my other 2.0 tdi's also failed that gas indicator test when I later tried it on them and there is nothing really wrong with any of them. Although that said, my 2018 Passat with 40,000 kms on the clock dropped 200ml of coolant since it's last service. The car is still under warranty so I'm still actually paying the ridiculous money VW look for to service it. I mentioned when I was picking it up that I had to top up the coolant pre service and they told me there was absolutely nothing wrong with the coolant system. I noticed when I got home however that they had completely filled the coolant tank up to within a couple of cms of the top, never saw that before but I like their solution :)
 

Kel8117

Member
Joined
Feb 8, 2021
Location
UK
TDI
VW Golf MK7 GT TDI
Thanks again all. Great info and advice @‘shocks’ I will see if I can locate the recommended Nissens heater matrix and have it delivered overseas in time 👍🏻
 

MaximisDoom

New member
Joined
Oct 18, 2020
Location
Nottingham UK
TDI
2.0 184
MaximusDoom, I would strongly advise you to find a new mechanic. The magic tools he's referring to cost about a hundred quid and even though doing a head gasket repair is time consuming, it should be well within the ability of anyone claiming to be a mechanic. Any independent specialist VAG mechanic should be able to do any VAG repair without exception, even adaptations requiring factory authorizations.

I also wouldn't advise anyone to start with the assumption it's a blown head gasket. The very large majority of people on this forum have fixed their issues with a heater matrix change and this in my opinion should be the starting point for most people in the affected mileage/age range we have seen.

What sort of head gasket test did this "mechanic" do, a gas test isn't conclusive as I found out when I decided to change my head gasket out based on results of one of these tests. I did this head gasket replacement by myself by the way, and without having burglarize a dealership for tools as well mind. I found nothing wrong with the head gasket.

Unfortunately, I didn't discover this helpful thread until I was halfway through that exercise, after putting everything back together I was still getting blowouts of coolant. Once I changed that Matrix though, voilà, problem gone!
I dont want to dilute the thread with any form of arguing but feel compelled to reply to your, somewhat, sarcastic reply. I am not a mechanic by trade but I am also a very logical person due to the job I actually do.

1. I don't have "a mechanic" I ask a few different mechanics that are either recommended or have a good reputation. There are 3 VAG specialist mechanics in my area and 2 Seat dealers, all of which gave the same answer when it came to repairing the head. Very difficult to do without the correct tool, which they cannot get (specialists) and much easier/cheaper to replace with a used engine than repair (specialist & dealer).
I told none of them anything other than I was getting coolant blow outs and I suspected that it was the head gasket. They all suggested it could be other things but I asked 2 of them to test for head gasket issue (both very reputable specialists) which cost me a fair bit due to the doing diagnostics checks, gas tests and compression tests. Both of them made videos of their tests as this is part of their service. This showed the liquid turn green when gas was tested via the coolant expansion tank and the pressure dropped in one of the cylinders.

2. The tools aren't "magic" and I certainly know the ones that are available are most definitely not a hundred pounds or so, they range into the thousands of pounds as a matter of fact. Perhaps you could send me a link to where you would purchase the cheaper versions of these tool? Always good to be in a mechanics favoured customer list.

3. I NEVER said to start by assuming it's your head gasket. I said that it might be a good idea to get that check first before spending money on other things, as in my case.

4. After the tests and the month or so of dilliberating if I should get it mended or just get a new car, I started to get other issues. Like when I went on a drive for more than 30 minutes and the engine and coolant had time to get up to temp and pressure I would obviously stop and it would cool. I'd then go to start it again and it would turn over slightly, stall, then start but only run on what I assume was 3 cylinders, then clear up after a few seconds. If I removed the coolant cap to release all the pressure before letting it stand it would start as normal.
There was also a build up of a creamy residue on the inside of the oil cap after around 3 weeks.

One thing I will say however is that a good piece of info I had regarding the heater matrix getting blocked was due the cooling system comprising of mixed metal parts. This means that the head is Alloy, the fins of the front rad are copper, the body is steal and the heater matrix is aluminium. This is why the coolant fluid is a specific type. All these metal make microscopic deposits in the water circulating the system, particularly aluminium, which then become corrosive to the other metals. The coolant fluid is supposed to prevent the reaction and if you top up with plain water or a different coolant it will accelerate the reaction. It is these deposited that block the heater matrix and create an insulating lining on the inside of the fins. Hence, even if you flush the matrix out it will often not make any different as it the layers of silt coating the fins that stop the heat transfer. A new matrix is often required.

Just to reiterate, I am NOT recommending you assume its the head gasket but just to get that checked so it can be eliminated as it makes everything else a waste of time IF the head has gone.
 

Kel8117

Member
Joined
Feb 8, 2021
Location
UK
TDI
VW Golf MK7 GT TDI
Thanks for the advice Maximis 👍🏻. I can’t recall any times I’ve suspected it wasn’t firing on all cylinders and there is no sign of coolant in the oil upon inspection of the cap or dipstick, it also doesn’t overheat. The coolant blow out seems to be associated with regen and various intervals, I can drive round town for an hour or 2 and it’s fine, then occasionally I come out check the expansion tank to see it wet underneath and coolant drop. The temp is always around 90 and engine oil at approx 100.
 

shocks

Active member
Joined
Jan 22, 2020
Location
Perth AU
TDI
Golf MK6 2.0TDI (103KW CFFB) Comfortline, Golf MK7 2.0TDI Highline (CRBC 110KW), Passat Alltrack Wolfsburg Ed. 2.0TDI (DFHA 140KW)
MaximusDoom, I definitely wasn't having a go at you and I'm not trying to start an argument, I know how frustrating this can be, remember I did a head gasket replacement by myself and it was for nothing, I'm just trying to make sure others don't go down this rabbit hole needlessly. I was having a crack at specialised mechanics telling a customer that they don't have the tools to do the job.

The additional information you provided is a bit more descriptive. I asked what tests they did because I believe the indicator test is unreliable as my dye turned green on all three of my TDi engines and none of them had a blown head gasket. Yes, the cylinder compression test failing on one cylinder is a bit more reliable and it sounds more likely you had a bad gasket or worse. You also had very different issues than most other people who have commented in that your issues actually affected operation and drivability of your vehicle.

Assuming it was just the gasket and not something in the cylinder head or valve gear that broke, I don't see how they could quote you the prices they did. I see your car is a 184kW version so it probably has variable valve timing, this could complicate a repair if the cam shaft adjustor or controller were affected but if it's just a head gasket replacement then probably not. I have looked at the procedure again and I don't see anything that requires particularly special tools. The only hardcore tooling requirements I see across all the cylinder head related procedures relates to removing and installing valve stem seals. A new cylinder head c/w valve assemblies might be a cheaper option if things got that bad looking at the setup and labour required.

The only special VAG tool I purchased for my head gasket replacement was a kit similar to this .. https://www.lasertools.co.uk/product/6809. There are even cheaper options out there. This is the same kit you need to change the toothed belt out too. All other tooling I needed was generic workshop stuff I either had or bought from the auto parts store. I would liked to have had the special injector puller but I made my own as they're quite expensive to buy.
 

Kel8117

Member
Joined
Feb 8, 2021
Location
UK
TDI
VW Golf MK7 GT TDI
Hi all, would anyone be so kind as to tell me if this is the correct Nissens Heater Matrix that has been proven the best to rectify this problem? Thanks in advance 👍🏻
 

shocks

Active member
Joined
Jan 22, 2020
Location
Perth AU
TDI
Golf MK6 2.0TDI (103KW CFFB) Comfortline, Golf MK7 2.0TDI Highline (CRBC 110KW), Passat Alltrack Wolfsburg Ed. 2.0TDI (DFHA 140KW)
Hi all, would anyone be so kind as to tell me if this is the correct Nissens Heater Matrix that has been proven the best to rectify this problem? Thanks in advance 👍🏻
According to the Golf Workshop Manual there are two different types.

The unit in your link looks like a replacement for car fitted with a Valeo Heater and Air Conditioning Unit. If your car has a Valeo system then this is probably the correct one. That's the type my car had.

If you car is fitted with a Denso Heater and Air Conditioning Unit then the unit your after will look like this with the pipes along the side ...



The manual tells you to use this difference to figure out which brand/type which isn't very helpful if you don't want to do any dismantling at this stage. Alternatively, call a VW parts department, give you VIN number and get a quote for the VW replacement part, my Valeo version was Part Number 5Q0819031B, I haven't had any issues but it was 315 Dollars from VW.
 
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