VW POLO 9N 2005 Heater Core / Heater Matrix issues

blis

Veteran Member
Joined
Mar 5, 2018
Location
Australia
TDI
1.9 TDI Polo 2006 (2005 built)
Thought I'd start a new thread for the 2005 and later VW models and heater cores. Having a MK2 GTI, its a beast of a task, dash out, whole heater module out and like many VWs a massive pain in the (_!_)
HOWEVER!!!
If the plumbing into the heater core looks like this, then you might be in for a good surprise!

You're probably good for a "dash in place" removal.
Here -> https://workshop-manuals.com/volkswagen/polo-mk4/heating_ventilation_air_conditioning/heating_air_conditioning/heating/heat_exchanger_remove_and_install/heat_exchanger_(behr_box)_remove_and_install/removal/
WARNING: ENSURE YOU DISCONNECT THE BATTERY !!!
DIFFICULTY: Moderate to mild.
NOTES:
  • The seats have spline drives to bolt the rails to chassis
  • My seats have airbags and they need disconnection (two of them)
  • I removed head rest and leaned seat forward max to get the seats out
  • Air Bag ECU required disconnection and has a press tab and level
  • There was another connection to allow the lower half of the heater housing to be removed.



So the first thing you'll want to do is remove the RHD drivers seat, center console, foot support and under dash trims.



Pull the carpet back a little and remove the side brackets to the console support. This will give you the clearance to swing the lower tray out.


I had to remove the Air Bag ECU as the picture in the workshop manual shows a lot more head clearance that I had. the lower part of the heater box housing was almost resting on the airbag ecu. Three 10mm plastic nuts and the disconnection and it was out.
 
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blis

Veteran Member
Joined
Mar 5, 2018
Location
Australia
TDI
1.9 TDI Polo 2006 (2005 built)
VW Polo TDI 1.9 9N MK4 2005/6 Heater Core Removal


So with the ecu and lower half of the airbox out of the way I went to the firewall to see what fixing was holding the piping the matrix...

All good and easy, well it was but it was quite tight too!! Really tight, so tight it had me worried. It's quite a long thread and like any task working close to a firewall, it took some patience. I removed it from the underside, there's nothing to say you can't remove it from the top.


With it removed I went straight to the sink with soapy water and gave it a clean, removed what seemed to be traditional VW perished foam and filled it looking for leaks etc.. With a frown on my face, I found none! I've removed the Golf MK2's and it was split but this heater core is much nicer, it's metal capped and looks like it's meant to last.. so a little more head scratching was in order.


 
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blis

Veteran Member
Joined
Mar 5, 2018
Location
Australia
TDI
1.9 TDI Polo 2006 (2005 built)
Matrix on the desk - Bracket orientation.

With the matrix removed, washed down with no signs of leaks I went back to the workbench to do some investigation. Here's the connection as it came off the car.

I cleaned up the pipe ends, had some o-rings and tried a few until I found a good seal. Here it is with two, one smaller and the other the same size as the ones on the car as I found it. I also found another VW bolt from my trusty VW bolt box that had a built in washer.

NOTE: I've turned the bracket around the other way, I'd noticed some deflection on the bracket and the ridges on it press the pipes in more securely. Would love to know your thoughts. With the bracket set the other way round, the pipes didn't press into the flange as snug. I'm still brewing my thoughts about the best way to proceed while I'm posting the thread.


The more I look at the pics the more I'm convincing myself that the bracket to the flange presses better with the lip facing down.

 

blis

Veteran Member
Joined
Mar 5, 2018
Location
Australia
TDI
1.9 TDI Polo 2006 (2005 built)
I idled the car to full operating temps last night, saw no leaks... However, I didn't seem to get the cooling system up to full pressure so we'll just have to see how we go.

I'm leaving the flange clamp in the opposite configuration to how it was installed, it seems to seat the pipes into the flange more securely and there's less deviation in the clamp itself. Installing it with the base down allows the semi-circular pipe section to flex upward and also bottoms out the clamp against the flange. I can't think of anything that can cause issues later on, so I'm moving forward as is..

TBC
 

Tdijarhead

Top Post Dawg
Joined
Nov 10, 2013
Location
Lawrenceville PA
TDI
2003 TDI Jetta Daughters Car, 2001 TDI Beetle, Wife’s car, 2005 Golf TDI Mine, all 5 spds
To achieve full operating temperature you’ll need to bring your temperature up to 190F or I think 88-90C as reported by vcds. My temp gauge reaches straight up at 164F, I have an ultragauge hooked up to read various functions and water temp is one of them.

So going by the gauge in the car is inaccurate. Although I don’t think you’ll have any problem bring the car up to full temp in a short time, since you’re in such a warm area.

Any chance someone changed the matrix out before and put that bracket in backward?
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
Just to be clear, the A2 heater cores are not hard. I think I had the HVAC case out in under an hour after a few jobs. You do not have to take the dash out, either, just loosen it.

That said, I wish they sold the Polo here.... looks like a neat little car.
 

Tdijarhead

Top Post Dawg
Joined
Nov 10, 2013
Location
Lawrenceville PA
TDI
2003 TDI Jetta Daughters Car, 2001 TDI Beetle, Wife’s car, 2005 Golf TDI Mine, all 5 spds
Just to be clear, the A2 heater cores are not hard. I think I had the HVAC case out in under an hour after a few jobs. You do not have to take the dash out, either, just loosen it.
That said, I wish they sold the Polo here.... looks like a neat little car.

They do look like a nice little car, although someone put all the controls on the wrong side. I wonder if that was intentional? :)

Thanks oilhammer for chiming in on his turbo problem, looks like he has that mostly worked out.
 

blis

Veteran Member
Joined
Mar 5, 2018
Location
Australia
TDI
1.9 TDI Polo 2006 (2005 built)




She's a brilliant little car, no whistles and bells but everything you need. Heater core was fine, perhaps there was a misunderstanding because my wife said the floor was wet and smelt sweet.. probably burst a bottle of soda in the shopping.. who knows.. To check the heater core I used some rubber grommets and compressed air in a tub full of water and couldn't find a leak anywhere. So cleaned it up and put it back in. It's a nice piece of kit too, very nicely made. Probably why there's no mention of failures online.

NOTE: Looking into the heater core the passages are quite narrow and if there was any sign of contamination in my coolant, I would have flushed the engine and treated the heater core with vinegar etc..

Went for a drive and my feet were all nice and warm again. We live in the sub-tropics so it's not always needed, but as winter comes, the humid air condenses quite badly and we can't see out the drivers window. So it's more a demister function we need. Using the air con just freezes up the condensation on the outer of the window and it's simple science that the window has to be warmer than the air, and that's done now and I'm at peace.

The interior wasn't to hard to negotiate with, it's the spline bolts that will catch people out as it's definitely worth removing the drivers seat. The console is three pieces, with the last piece being the bottom that wraps around the heater core housing. I tried to remove the gear know but that seemed futile so the gear stick cover remained in place. It's a bunch of torx screws and a little wiggling around with the handbrake in the UP position and it's out.

I think the only thing that I couldn't really get to was the firewall grommet. There's a groove around the flange of the heater core that I assume the lip of the grommet slips into. Regardless, it was a surprisingly easy job and the dash didn't need to be touched at all, just the airbag ECU needed moving out of the way. Clips were easy to remove and install too!

Much easier than the MK2s :)
 
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BobnOH

not-a-mechanic
Joined
May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
This looks like good information, might be nice to have at least a link in the model specific forum. I'd do it, but I don't even know what it is.
 

blis

Veteran Member
Joined
Mar 5, 2018
Location
Australia
TDI
1.9 TDI Polo 2006 (2005 built)
This looks like good information, might be nice to have at least a link in the model specific forum. I'd do it, but I don't even know what it is.
I don't think they are produced/imported into the US... The Engine is an AXR and because the model isn't categorized, it was suggested that it best lives in the 101. Which is fine by me :)

Globally it's known as a MK4 Polo - This one (I think) was made in South Africa and imported into Australia as it was more common (almost all) to have the 2.0 TDI in the Golf's I haven't seen a 1.9 Golf in Australia. In later years the Polo had much smaller TDI engines and the 1.9's aren't as common. It's a light car with very torquey engine and we love it.
 
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BobnOH

not-a-mechanic
Joined
May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
That's the same family as the BEW (wikipedia). Being an MK4 the interior bits may be similar to the PDs sold here.
 

Tdijarhead

Top Post Dawg
Joined
Nov 10, 2013
Location
Lawrenceville PA
TDI
2003 TDI Jetta Daughters Car, 2001 TDI Beetle, Wife’s car, 2005 Golf TDI Mine, all 5 spds
That’s great! Glad to hear it’s coming together for you. How’s the smoking/turbo issue?
 

blis

Veteran Member
Joined
Mar 5, 2018
Location
Australia
TDI
1.9 TDI Polo 2006 (2005 built)
That’s great! Glad to hear it’s coming together for you. How’s the smoking/turbo issue?
With Turbo, I am none the wiser... we've had NO more issues other than the EGR Manifold Pressure Flap still disconnected. I am no longer getting the hesitation, nor the rattling sound (which I "think" could have been an EGR Actuator problem) Car has no lag, no hesitation, it's back to it's old self, goes like a rocket, no smoke at all... engine sounds happy, wife's happy... I'm happy. (Specially that the impellers were nipped by old impeller debris, getting lots of boost)
As for the Heater Matrix, I'm stumped as to why my wife said it was leaking and in hindsight, the quality of the matrix itself is "top shelf" so that's why I think there's so little info out there on them failing.
If one is totally OCS then I'd say the hardest part of the job would be ensuring the rubber grommet at the firewall seats into the groove on the heater matrix flange. That'll ensure there's a good seal between firewall and the cabin.
It's probably a good time to have checked the filter too, but I had my hands full in other areas and I wanted to get the stereo system ground to the brake lever to cover my (_!_) against insurance issues later on. Apparently it's a common loop hole for them to void claims because the wire was not terminated correctly, so that was more important
Got to give the driver's side a good vacuum, the seats aren't too difficult to deal with but the connectors had me fussing about. One screw was missing from the connect bracket, which has spaces for several other fittings. The Air bag fitting had a sprung cap as added security and took a little care to disconnect. Helped having the boys to get their heads right up to the firewall to get a look. Those hard to reach places I don't go, I use the camera and I should invest in good mirrors
So pleased VW changed from a vertically high mounted matrix and saw much better service to have it down low and accessible.:)



 
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Tdijarhead

Top Post Dawg
Joined
Nov 10, 2013
Location
Lawrenceville PA
TDI
2003 TDI Jetta Daughters Car, 2001 TDI Beetle, Wife’s car, 2005 Golf TDI Mine, all 5 spds
These heater cores that get buried are a real pain. The first one I ever changed was a Ford Aerostar, couldn’t believe how easy it was and I didn’t understand why everyone was so reluctant to change one out. Then I changed the core on a mercury tracer. I found out in a big hurry why people don’t like to change Heater cores.

I’m glad you’ve got this sorted out now to figure out the egr thing and you’ll be all set.
 

Yerhan

New member
Joined
May 12, 2018
Location
Istanbul
TDI
1.4
Hello blis,
Thank you very much for this detailed explanations about heat core removal. I have a Polo 2003 mk4 9N and I realised a leakage when I saw the warning on cluster.
I took my car to some services to understand where is the leakage. After that we decided it's from heater core or its connections. I tought it's from the connections, because there was no leakage into my car. When we removed the heater core with your grateful support, we saw that the heater core was dry and one of the grommets was damaged.
We changed the damaged grommet but we could not assemble the heater core again because of the problem you mentioned "I think the only thing that I couldn't really get to was the firewall grommet. There's a groove around the flange of the heater core that I assume the lip of the grommet slips into."
We're not sure that the lips of the grommets slip into. Is there any easy way to be sure or what is the optimum location for this assembly? We tried to assemble it from both underside and top of the vehicle but we couldn't.
 

blis

Veteran Member
Joined
Mar 5, 2018
Location
Australia
TDI
1.9 TDI Polo 2006 (2005 built)
Hello blis,
Thank you very much for this detailed explanations about heat core removal. I have a Polo 2003 mk4 9N and I realised a leakage when I saw the warning on cluster.
I took my car to some services to understand where is the leakage. After that we decided it's from heater core or its connections. I tought it's from the connections, because there was no leakage into my car. When we removed the heater core with your grateful support, we saw that the heater core was dry and one of the grommets was damaged.
We changed the damaged grommet but we could not assemble the heater core again because of the problem you mentioned "I think the only thing that I couldn't really get to was the firewall grommet. There's a groove around the flange of the heater core that I assume the lip of the grommet slips into."
We're not sure that the lips of the grommets slip into. Is there any easy way to be sure or what is the optimum location for this assembly? We tried to assemble it from both underside and top of the vehicle but we couldn't.


Im not entirely sure the grommet will make a major difference but we don't have salt and snow etc here. But we've had no issues since and no leaks either. The grommet is still there it's just not tucked over the lip of the matrix

 

poloyolo

Member
Joined
Aug 5, 2018
Location
here
TDI
polo sdi
seems like i have the same issue, losing coolant a lot, and mi firewall is wet on the outside
i was wondering, what size are the o rings so i can buy them before the job, and do they need to be some special kind?
Is it possible to do it only from outside without touching the dash?
do i need to let all of the coolant out before i start? what needs to be removed in the engine bay to access the heater pipes, and would you recomend the job for a slightly experienced "mechanic" like me?
i usually do the oil and brake jobs myself..but this look scary
tnx

one more question, where did xyou get that dash cover :D ?
 
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blis

Veteran Member
Joined
Mar 5, 2018
Location
Australia
TDI
1.9 TDI Polo 2006 (2005 built)
seems like i have the same issue, losing coolant a lot, and mi firewall is wet on the outside
i was wondering, what size are the o rings so i can buy them before the job, and do they need to be some special kind?
Is it possible to do it only from outside without touching the dash?
do i need to let all of the coolant out before i start? what needs to be removed in the engine bay to access the heater pipes, and would you recomend the job for a slightly experienced "mechanic" like me?
i usually do the oil and brake jobs myself..but this look scary
tnx

one more question, where did xyou get that dash cover :D ?
I used some from a kit, I'm sure if you pick up a mixed kit, youll find a pair that will do,.

Dash cover... I was lucky and ordered it when we bought the car. can't remember where sorry. But it's a perfect fit, so someone makes them :) Sorry couldnt bemore helpful,
 

vwali

New member
Joined
Jun 9, 2021
Location
UK
TDI
-
Matrix on the desk - Bracket orientation.

With the matrix removed, washed down with no signs of leaks I went back to the workbench to do some investigation. Here's the connection as it came off the car.

I cleaned up the pipe ends, had some o-rings and tried a few until I found a good seal. Here it is with two, one smaller and the other the same size as the ones on the car as I found it. I also found another VW bolt from my trusty VW bolt box that had a built in washer.

NOTE: I've turned the bracket around the other way, I'd noticed some deflection on the bracket and the ridges on it press the pipes in more securely. Would love to know your thoughts. With the bracket set the other way round, the pipes didn't press into the flange as snug. I'm still brewing my thoughts about the best way to proceed while I'm posting the thread.


The more I look at the pics the more I'm convincing myself that the bracket to the flange presses better with the lip facing down.

Do you know what size of bolt is required for reconnecting the heat exchanger to the bracket?
 
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