Golf GT TDI MK7 No heat from vents

Golf GT TDI MK7 No heat from vents

Author
Discussion

Chris_W_

1 posts

59 months

Wednesday 29th May 2019
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Can anyone assist further on this? I have a 63 plate MK7 GTD that heater does not get hot and keeps loosing coolant. No sign of any leaks.

phil633

175 posts

214 months

Friday 31st May 2019
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More than likely tea bag in header tank has split. Or is casting sand from when block is cast. Just fitting matrix is unlikely to cure longterm. The flushing process is a complicated operation involving shutting and opening various parts if cooling system at different points.

Candellara

Original Poster:

1,876 posts

182 months

Saturday 15th June 2019
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Chris_W_ said:
Can anyone assist further on this? I have a 63 plate MK7 GTD that heater does not get hot and keeps loosing coolant. No sign of any leaks.
Thread resurrection time. After many months of the car being fine, the problem has reoccurred. I'm guessing that the silicant has blocked the matrix again. Anyone had any luck / insight into this?

I cannot see any coolant bleed valves on the mk7 2.0 tdi - any VW techs on here to share some insight?

Rossko37

2 posts

56 months

Wednesday 14th August 2019
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Hi. Anyone had any success with this. I’ve got the same problem with my 2015 A3 diesel. Took it to an independent German garage, n they have said the silica bag has burst inside the tank n blocking the system. Said it’s quite complicated, and there’s 3 circuits needing flushed out. They said the only people that can do it are Audi, because the don’t sell the flushing solution to the trade. Audi want £1200. Surely if there’s no recommendations to change coolant or tank, this is a design fault with the car. Only starting to hear about it now, cause I’ve been told they only started doing it a few years ago. Any help appreciated

Patch1875

4,894 posts

132 months

Sunday 10th November 2019
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Can add my GTi to the list.

Pretty much no heat at all. After a while it does go marginally warm.

All the same from all the vents air con seems to work for the cold ok it’s had a thermostat and water pump done in the last year or so.

Hopefully not the matrix as that seems expensive!

Patch1875

4,894 posts

132 months

Wednesday 27th November 2019
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Turns out the matrix was blocked due to the bag in the header tank splitting and causing the blockage.

New matrix and header tank fitted at a VW indie £500.

Very common on MQB platformed cars apparently.

davebem

746 posts

177 months

Wednesday 27th November 2019
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I removed the bag from mine as preventative measure, I guess its there to preserve the life of the coolant. Id rather just replace the coolant every 4-5 years.

Patch1875

4,894 posts

132 months

Wednesday 27th November 2019
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davebem said:
I removed the bag from mine as preventative measure, I guess its there to preserve the life of the coolant. Id rather just replace the coolant every 4-5 years.
The header tank is now modified and no longer has it.

Didn’t know about it if I did I would have removed it also!

rickygolf83

290 posts

161 months

Tuesday 3rd December 2019
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davebem said:
I removed the bag from mine as preventative measure, I guess its there to preserve the life of the coolant. Id rather just replace the coolant every 4-5 years.
4-5 years is a long time.

For all it would cost, 2 years seems a better preventative measure if that is the objective. Brake fluid should be done on the same interval

Rossko37

2 posts

56 months

Monday 13th January 2020
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Put my 2015 A3 in to Audi. They have said there is casting sand in engine coolant and have agreed to repair it as a good will gesture even tho car is out of warranty. They had the car over 1 month. I then got it back after they had flushed it and replaced heater matrix. Exact same thing happened day after I got the car back. Put it back in straight away. They still have the car. That’s 4 months it’s been in the main Audi dealership. They have said there is a backlog order on heater mateixs, and they are waiting on one coming from Germany. They also said it wasn’t flushed out properly the first time.

J44BLR

1 posts

50 months

Wednesday 5th February 2020
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Chris_W_ said:
Can anyone assist further on this? I have a 63 plate MK7 GTD that heater does not get hot and keeps loosing coolant. No sign of any leaks.
Hi Chris,

I am having the same issues on my MK7 Golf GTD on a 14 plate. For the coolant issue i was advised to have the EGR cooler replaced, however thereafter it is still losing coolant. Also the vent is not producing heat too. Could you please advise me if you got these issues sorted? Thanks!

BillyCool

1 posts

50 months

Friday 7th February 2020
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Hiya - this thread has been really useful. I'm having a similar problem.

Seat Leon ST FR 2.0 TDi 184bhp 2014 90,000 miles

Recently found that after a 100 mile or so motorway journey the car would lose some coolant. I didn't notice it when driving but the air vents went cold (should have twigged), no warnings/lights. I did notice on arrival at destination the dashboard (heater matrix?) was `gurgling` a bit. On leaving the car parked and starting up I get a low coolant warning (there is a tiny amount at the bottom of the expansion tank). Top up and drive on. Get to the other end, check and all is well.

Also noticed that heater on drivers side very tepid yet boiling hot on passenger side.

More recently and more worringly, over the last 7 days the car has started to overheat. Drive to work (19 miles) - 15 miles in, car nice and warm, just tootling along (50 limt), boot it onto some dual carriageway and 10 seconds later water temp warning (off the scale), "stop now". Minor soiling of underwear and I pull over ASAP. I assume that I have dumped all of my coolant and cooked the engine. Lift bonnet, no smells, no tincking of red hot metal. I expect to see no coolant in the expansion tank but it's up to the line.

So - do I have a bigger issue?

The car now gets up to temp (90 degrees) within 2 or 3 minutes. I'm sure that's not normal. It stops at 90 degrees unless I boot it an then it can jump up to 98, 103, then drop down and maintain 92 or 94. Really variable. I also find that the coolant pipes that I can access and squeeze, aren't that firm don't seem to be under that much pressure (certainly not for a sealed unit when the engine has been running for 35 mins)

Having read this forum back to front and other Seat related posts, I'm sort of none the wiser to the exact cause - BUT - I have a very long list of possible isues:

Initial loss of coolant and heater issue:
- Blocked heater matrix? (expansion tank does have a silica bag label on outside but can't see the bag, so could be an issue)
- Leaky expansion tank
- Faulty coolant temp sender
- Sticky heater flaps/motors/widgets

Plan A was to deal with the first 3 things and replace all 3. They are more or less the cheaper DIY fixes that I can do. Not sure about motor flaps.

I have seen on here mention of the EGR cooler and possible issues with DPF regens. That's not feaured on my radar yet.

Now the car is overheating, do I have other potential issues:
- Faulty thermostat
- Knackered (or soon to be) water pump
- Blocked hose(s)
- Other part I don't know exists yet that is contributing to the problem

Don't think it's head gasket (hope not).

So - as a combination of symptoms I'm wondering whether a silica gel/matrix issue is causing poor coolant flow other things to block up and/or fail as well.

The plan is to replace the plan A items and see what happens.

Plan B is to get it into the garage for:

-New water pump (the cambelt is due soon so will get that done as well so 2 birds etc)
-New thermostat

That way I've covered most bases.

The car had a service last week and I asked my mechanic to have a look at it (he didn't have time to start taking stuff apart). He said there was a little coolant witness mark around/close to the water pump, so it could be that. I've seen a document that mentions issues with the coolant pump actuator.

"This has been reported to us before and it affects Leon ST models with CXXA/CXXB engine codes. The fault is due to a failure of the engine coolant pump impeller control actuator. Remove the engine coolant pump. Check if the engine coolant pump impeller control actuator is stuck in the closed position (see figure above), then fit a new engine coolant pump."

My car is a CUPA engine code :-(

So - no obvious easy fix but a list of things to work on.I have not got to VCDS scanning yet. My mechanic will do that before anything too expensive takes place. Not ideal but I need to sort it. My previous Mk1 Leon TDi did 220,000 miles over 10 years and I NEVER had these sorts of isues. Modern cars are so over-engineered.

Sorry for the essay but I've found a lot of stuff on the forum really helpful. I'll post an update if I get to the bottom of it.




anon4321

1 posts

50 months

Friday 7th February 2020
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I found this thread searching for 'mk7 golf no heat from vents'.

Lots of the results on google say that the dashboard has to be taken out to get to the matrix.

That is not true, you can get to it by removing the glove box. Here is a video (not mine):

https://www.youtube.com/watch?v=Yh8BwjJgkiI

I've removed everything apart from the heater core itself, I'll get the garage to do that bit (even they said they'd need to take the dashboard out).

Edited by anon4321 on Friday 7th February 12:54

Steve UK

290 posts

186 months

Saturday 10th October 2020
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Did you replace the matrix for another VAG one?

It does seem the cores are to small? I have a 2013 GTD, last week I fitted a new water pump/cambelt due to overheating. This is now fixed and the sleeve on the pump was sticking.

The heater did randomly improve but now fairly poor again, I have a replacement waiting to be fitted from here http://www.motoradsonline.co.uk/products/Volkswage...

It seems good quality, maybe outright performance maybe a bit down on the VAG part but should fix the problem. Fingers crossed.

Steve UK

290 posts

186 months

Wednesday 28th October 2020
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All fitted, nice easy job. 2 hrs maximum. Has been a couple of weeks now with no coolant blowing out the expansion bottle and the heater is lovely and toasty. Just in time!

I also decided to reclaim my old solenoid from the old water pump and plug this into the loom rather than the new pump. The idea being the pump never disabled when cold and in theory never get stuck shut. I guess it takes longer to warm up but not that I can notice.

Straight-Sixx

7 posts

78 months

Saturday 7th November 2020
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I have this very issue and I am a bit worried really! 2013 Golf GTD with 50k miles. Read all of this and other forums but my issue is I cannot see the bag in the coolant bottle and the coolant is still bright pink so not discoloured. Little hot air in the cabin so it looks/sounds like the matrix but I am just wondering where this bag has gone. There doesn’t seem a definitive answer and I don’t want to be going down the route of replacing when it’ll just return again. I did notice my fuel consumption also increased so could it be an egr issue?

Edited by Straight-Sixx on Saturday 7th November 08:30

Patch1875

4,894 posts

132 months

Saturday 7th November 2020
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Check the water pump as well they can leak and affect sensors in the thermostat housing.

Straight-Sixx

7 posts

78 months

Saturday 7th November 2020
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It had water pump and cam belt not a couple of thousand miles ago...

Straight-Sixx

7 posts

78 months

Monday 9th November 2020
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So is it a matrix change and wait till it happens again or are people just running the cars with the fault till it fully gives up? I don’t suppose there is any help from the dealers?

WORKINGALLWEEK

13 posts

164 months

Friday 4th December 2020
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Casing sand seems to be an issue with VAG engines . My Skoda Scout 2016 is in again for the second time now . i have a oic of whats floating around the coolant .