Golf 2013 no heat inside, blocked heater matrix, any ideas

[Dicky300]

Hi ,

We noticed there was no heat from inside the car recently.
Pipes going to bulkhead are red hot., expansion full.
Temperature gauge normal.
Tried running rad flush through it and nothing.

Went to main dealer and he wants £1200 to change exp tank and test??!!?!?!?

Any help appreciated.

[bigjobbo]

Can I assume we are talking Golf 7? If so some models had a silica satchel (mit silica written on tank) inside the expansion tank which can burst and circulate the system and cause blockages at the narrow inlets, charge cooler and heat exchanger are prime, radiator is usually ok as the system is designed to pump coolant into the cabin via EGR from cold, only at 45* does coolant begin to flow to charge cooler and then at op temp, radiator. Also, casting sand left in the block during the manufacturing process can be a cause and usually causes a discoloured expansion tank (brown stains). Depending on severity it can be reversed, but it is labour intensive and the end product requires a vacuum cooling system fill and then a circulation which can only be done on a diagnostic machine and takes approx 35 mins at main dealer. Back feeding heat exchanger and charge cooler with a hose, ideally using warm/hot water to expand the channels, you should see the blockage come out in the form of discoloured water. Be prepared to do multiple flushes and use a lot of water at a reasonable pressure. You will see improvements but a 100% fix may take multiple cycles ie flush-fill-use-flush-fill-use etc. Main dealers have a flushing kit, it takes approx 2 hours and they will likely advise replacement of heat exchanger and charge cooler plus any other contaminated parts. I must add, heat exchanger replacement does not require dash out and is accessible via the left side centre console panel and can be replaced reasonably easily. The only downside to draining the cooling system and most work on the cooling system, is the refill process, it’s absolutely necessary it’s carried out to enable the three cooling systems to operate correctly and premature wear can occur if it’s ignored.

If you do own a very late Golf 6, ignore that post and check your water pump is circulating

[Candellara]

bigjobbo said:

Can I assume we are talking Golf 7? If so some models had a silica satchel (mit silica written on tank) inside the expansion tank which can burst and circulate the system and cause blockages at the narrow inlets, charge cooler and heat exchanger are prime, radiator is usually ok as the system is designed to pump coolant into the cabin via EGR from cold, only at 45* does coolant begin to flow to charge cooler and then at op temp, radiator. Also, casting sand left in the block during the manufacturing process can be a cause and usually causes a discoloured expansion tank (brown stains). Depending on severity it can be reversed, but it is labour intensive and the end product requires a vacuum cooling system fill and then a circulation which can only be done on a diagnostic machine and takes approx 35 mins at main dealer. Back feeding heat exchanger and charge cooler with a hose, ideally using warm/hot water to expand the channels, you should see the blockage come out in the form of discoloured water. Be prepared to do multiple flushes and use a lot of water at a reasonable pressure. You will see improvements but a 100% fix may take multiple cycles ie flush-fill-use-flush-fill-use etc. Main dealers have a flushing kit, it takes approx 2 hours and they will likely advise replacement of heat exchanger and charge cooler plus any other contaminated parts. I must add, heat exchanger replacement does not require dash out and is accessible via the left side centre console panel and can be replaced reasonably easily. The only downside to draining the cooling system and most work on the cooling system, is the refill process, it’s absolutely necessary it’s carried out to enable the three cooling systems to operate correctly and premature wear can occur if it’s ignored.

If you do own a very late Golf 6, ignore that post and check your water pump is circulating

Chris - i think we have exactly the same issue with our 2013 Golf GT TDI. Just replaced the expansion tank and the problem seems to go away when i flush the heater matrix. Can you elaborate on the refill process?

[Candellara]

Worth updating this:

As stated, 6 months ago (during a motorway drive) we lost heat to the vents and we had gurgling noises from the dash. The car was subsequently booked into VW and their diagnosis was that there are no fault codes present but was is common on MK7 Golfs was that the silica bag in the water expansion tank ruptures and blocks the heater matrix. Price to rectify £819 for new matrix.

I didn't believe them and was a bit miffed that they hadn't tried to flush the system so i took the car away. I disconnected the hoses from the matrix at home and flushed with a hose and water was flowing freely. Upon reconnecting & top up, heat from the vents again!! The car only does local town driving and everything has been well for 6 months UNTIL, a recent motorway drive. Same symptoms, no heat from vents, gurgling noise and some water being forced from expansion tank on this occasion.

After returning home, i ordered a new expansion bottle & cap - very low cost and really to eradicate these items from being any cause. After fitting and checking, we have heat again from the vents.

Well, today i opened up the old expansion tank with a saw - and, the silicant bag is not ruptured and fully intact with all of it's crystals!!!!! Now this is becoming farcical as the amount of threads there are all over the forums about this exact problem and VW continuing to replace heater matrix's. One poor lady has had 3 heater matrix's as the VW dealer insists that the silicant granules have contaminated the system and continue to block the new heater matrix's. Indeed my local VW dealer wanted to relieve me of £819 for replacing the matrix - when we now know the matrix isn't blocked and the silicant bag intact.

Don't know where to go with this now but a VW technician in the States reckons it's a problem with one of the two electric coolant pumps (with plastic impellers that end up spinning on their shafts intermittently)

Any thoughts?

[Dom20013]

Hi did you manage to get a fix on this, I have the same issue flushed the matrix and heat was there for a short time now the heat is gone again.