No heat/cold air in 2018 Golf

[Magpie1862]

My 2018 Golf 2.0 Diesel GT has a problem with the air con.

In the summer, the cold air setting doesn't do anything so I have to wind the windows down.
In the winter, the warm air setting does nothing.

The very good independent VW garage I use, say it needs a new water pump, timing chain and the heater matrix replacing/.
I am not a technical person so don't know why all that needs doing.

The water pump/timing chain were only replaced 2 years ago.

They say re-gassing the air con will sort out the cold air but not the warm air issue.

Estimated cost of all the work £1,500.

I am reluctant to spend that amount on a 7 year old Golf but as the weather is getting colder, don't really want to have to wear gloves and 3 jumpers when driving.

Any ideas on what the actual root cause could be ?

Thank you

[NotNormal]

No heat is quite possibly because the heater matrix is blocked by the cilica beads that have come out the stupid bag that VW/Audi group stick in the header tank. Is a very common problem and I had to do this job on my wife’s 2017 S3 earlier in the year.

When your matrix is replaced make sure you take the bag out, and leave it out, to save it happening again in the future.

[stevemcs]

See if you canr get the temp reading of the heater pipes going into the matrix, if its hot going in cold coming out then its likely blocked.

If the engine gets up to temp then i don't think it can be the water pump, again yoou can feel the hoses.

WE have also had the odd issue where the AC has messed with the cabin heater.

[Magpie1862]

NotNormal said:

No heat is quite possibly because the heater matrix is blocked by the cilica beads that have come out the stupid bag that VW/Audi group stick in the header tank. Is a very common problem and I had to do this job on my wife s 2017 S3 earlier in the year.

When your matrix is replaced make sure you take the bag out, and leave it out, to save it happening again in the future.

I got another garage to remove the silica bag about 3 years ago for that very reason so can't seeing being that, unless it was already blocked.

Many thanks

[Magpie1862]

stevemcs said:

See if you canr get the temp reading of the heater pipes going into the matrix, if its hot going in cold coming out then its likely blocked.

If the engine gets up to temp then i don't think it can be the water pump, again yoou can feel the hoses.

WE have also had the odd issue where the AC has messed with the cabin heater.

Thanks Steve.

I am not mechanically minded enough to do this. I put fuel in and monitor tyre pressure.

I might have to bite the bullet and just get it fixed. £1,500 is better than say £20k for a new car.

I will ask the garage if they can just check the matrix for blockages, IF you can do that without having to remove the water pump/timing chain.
I don't know what is connected to what. The garage did say it is a labour intensive job, hence the cost.

[mattvanders]

I had my heater matrix go on my Audi tt last year, as much as heated seats are great having an actual heater to clear the windscreen properly on colder days is even more important. Worth getting the system draining out a few times to ensure it is full clear and won’t clog up the new heater matrix.

[stevemcs]

Magpie1862 said:

Thanks Steve.

I am not mechanically minded enough to do this. I put fuel in and monitor tyre pressure.

I might have to bite the bullet and just get it fixed. £1,500 is better than say £20k for a new car.

I will ask the garage if they can just check the matrix for blockages, IF you can do that without having to remove the water pump/timing chain.
I don't know what is connected to what. The garage did say it is a labour intensive job, hence the cost.

You don t need to be, open the bonnet, at the back will be 2 pipes that go through the bulkhead, one goes in, the other comes out, see if they both feel warm.

Under the dashboard, passenger side you will see a radiator, again one in, one out these are fed by the pipes at the back of the engine, if it s blocked the one going in will be hot, the one coming out cold - it can be very hot though so be careful

To change the heater matrix on a golf is a bit easier than the a3 as less trim needs to be removed, we allow 2-3 hours for this so around £400.

The blend motors can also fail - I haven t seen this on a golf but on a transporter, that s usually a dashboard out job.

We have a golf in tomorrow I ll see if I can get a picture, failing that I ll get one of my superb Which I think is the same.

Edited by stevemcs on Tuesday 18th November 19:08

[Magpie1862]

Thanks very much

[Drive Blind]

NotNormal said:

the heater matrix is blocked by the cilica beads that have come out the stupid bag that VW/Audi group stick in the header tank. Is a very common problem

i've heard quite a few stories where the bag being in or out makes no difference.

My experience,, my 2016 GTD showed the signs from about 70K miles onwards. The signs being the drivers side vent is cooler than the others. It got consistently worse until I sold it at 92K miles. My current 2019 Golf is now over 70K miles and is also starting to show the sign of the drivers side vent being cooler. Heated seats save you on the cold mornings.

A work colleague has a 2019 Golf 1.6 diesel at nearly 100K miles. All his vents were stone cold. He found a VW group specialist to do the job, they said they were doing at least one matrix change a week on the Golf/Leon/A3. A couple of places said the 'book price' for the matrix swap alone was over £1800! VW specialist did the matrix, timing belt and water pump for £1300.

[Magpie1862]

Thank you for your reply.

I can stand the cold in the cabin as I have a fair bit of insulation on me. The inside of the windscreen will take longer to defrost even with the fan speed on maximum.

My main concern is when my 89 year old mum is with me.

Good to know that a ball park figure of £1,500 seems about right. My VW specialist seems to be honest and fair.
Their labour rate is much cheaper than a VW dealer.

Don't think I will get another VW.
Reliability seems a common issue post the 1.9 diesel era.
My wife's Polo and Jetta were pretty poor.

Probably go Honda or Mazda.

[stevemcs]

Cambelt and waterpump is around £650/£700, matrix around £400

If the engine is getting up to temperature then it shouldn't be the waterpump

[Magpie1862]

Yes, the engine is showing as correct temperature on the dashboard guage.

Showing my ignorance here, but can the matrix be checked/replaced on its own, without replacing the water pump and timing chain ?

These were only replaced 2 years ago.

[stevemcs]

Magpie1862 said:

Yes, the engine is showing as correct temperature on the dashboard guage.

Showing my ignorance here, but can the matrix be checked/replaced on its own, without replacing the water pump and timing chain ?

These were only replaced 2 years ago.

No need to do both, yes they can be checked and changed seperatly.

[Deep Thought]

Magpie1862 said:

Yes, the engine is showing as correct temperature on the dashboard guage.

Showing my ignorance here, but can the matrix be checked/replaced on its own, without replacing the water pump and timing chain ?

These were only replaced 2 years ago.

I ran a 2014 Golf TDI for a couple of years there up until recently and had both heater issues and timing belt / water pump issues.

My gut feeling is - as has been said - if the car is getting up to temp fine (and not too quickly) and you're not getting overheating / and signs of instability of engine temp, then its not water pump.

My water pump and belt were placed as the pump got noisy, but they normally just leak / dump the contents of the coolant system out on to the road when they go. Unless its a fully electric one then it'll just stop and the car will overheat.

So my feeling is its heater matrix related. All the symptoms are there and thats what my car was doing / not doing when the matrix went.

Replacing it solved the problem.

And yes, you can do it without doing the water pump.

The garage are going for the sledgehammer approach and replacing everything it might be - and charging you handsomely for their lack of diagnostic ability.

[Magpie1862]

Thank you

They are all ex VW trained technicians and have always been very open and honest with their diagnosis and pricing.

I will ask them if they can just replace the matrix and pay accordingly.
If they find anything else, then I will have to suffer the pain and get it done.

Just driven to the pub and the car was bloody freezing inside.

Was only 1.5 degrees outside.
It will get colder.

[Deep Thought]

Magpie1862 said:

Thank you

They are all ex VW trained technicians and have always been very open and honest with their diagnosis and pricing.

I will ask them if they can just replace the matrix and pay accordingly.
If they find anything else, then I will have to suffer the pain and get it done.

Just driven to the pub and the car was bloody freezing inside.

Was only 1.5 degrees outside.
It will get colder.

I dont get why they're replacing both the water pump and heater matrix at the same time.

Both are very independent of each other.

[Magpie1862]

I did wonder that but don't have the technical knowledge to question such things.

Will let you know what they say.

[Deep Thought]

Magpie1862 said:

I did wonder that but don't have the technical knowledge to question such things.

Will let you know what they say.

And you don't have to be confrontational about it either. I think it's a reasonable question. Be good to hear their thinking

[stevemcs]

We had a vw master tech work with us for a short time, give me someone who has never worked in a main dealer anytime

The newer switchable waterpumps either - give a fault code or fail and take the engine with it.

The thermostats also play up but usually messes with the engine temp, we had a customer with one that played up, the main dealer told him there was nothing wrong despite him querying it a number of times, we replaced it, the car then got up to temp, wa about 5mpg better off and will never go back to skoda.

[CSR Performance]

It is a long shot, but before you spend any money, try this and see if it makes any difference.

https://www.youtube.com/watch?v=KJhaL65HL9Q