Heater Matrix Audi 80 b3 1.8s. Leaking ?

William Blyth · 27-08-18, 12:15 PM

Every time I go to a show something seems to happen! I went to the classic show at Ripon this weekend and the car decided to steam up (never has it done this before). I know it was raining but could I get the windscreen to clear ? No!
I tried the setting at hot, no luck, cold almost as bad, every thing I tried to keep the screen clear seemed a waste of time.
Got back checked the footwell It seemed a little damp but there again it was now full of wet grass from Ripon racecourse.
Checked under the bonnet for leaves in air intake, a found few. However I have foam blowing from my air vents so I'm starting to think it may be the heater matrix leaking? Has anyone had this problem?
I'm I right to believe it will involve hours of fun removing the dash etc or has anyone else found an easier way of checking for a possible leak in the heating system? Knowing my luck I will spend hours and hours removing the dash to find nothing wrong Any help gratefully received.

Mellis46 · 27-08-18, 01:11 PM

Chances are if your 80 hasn't ever had one, it now needs one purely based on age. Every B3 owner has to do this its almost a rite of passage!!

Yes, its a dash out job. The first time you do it it will take more than a few hours and you will find other bits and pieces to do along the way, heater flaps, wiring abortions and such like. There have been some very good how-to guides written over the years.

You'll know its gone if you are constantly topping up with water, wet footwells, excessive condensation, greasy film on windscreen etc. Foam from the vents - prob a safe bet your flaps at the very least have had it I'd say

Find where the lower vents are for the footwell on the passenger side, have a quick feel inside, if its wet there you have confirmed it without taking anything apart. This is where the matrix lives and is its lowest point.

Good luck!

sinbin5t · 27-08-18, 02:55 PM

As above, good advice !

William Blyth · 27-08-18, 04:05 PM

yep! have now left car to dry overnight in garage with roof open. Felt the bottom passenger airducts and are now wet with brown bitter tasting water! strange how things suddenly start- Saturday fine and heating working ok and on Sunday heater broken!

Mellis46 · 27-08-18, 06:50 PM

Thats how they go, all at once!

I feel your pain, BTDT on several occasions - you are about to embark on at least a weekend of stripping parts, drying carpets and insulation, bloody fingers and reducing your motor to a state it hasn't seen since it was being built! Good learning curve though, its a lot easier the second time round

William Blyth · 27-08-18, 08:55 PM

Whilst I'm replacing the matrix, and as foam has been blowing from the air vents; I must presume that the foam has come from the from the heater box vents ? Would that be correct ? and if so any idea of thickness of sticky backed foam required?

sjp001 · 27-08-18, 10:15 PM

I had to do this job on my b4 last winter, presumably similar to a b3? It took me all weekend to sort out, but the matrix itself is a cheap part. There is an absolutely brilliant walkthrough created by Paul Goodwin and Ian Simmonds found here: https://www.s2forum.com/articles/200...lacement-guide

I bypassed the matrix for a few weeks until I had time to do it. At least this stopped the carpets getting further soaked.

27-08-18, 01:11 PM	#2
Mellis46 Aero Advocate Classic Audi Club Member Join Date: Aug 2014 Location: Lancashire Posts: 1,448	Chances are if your 80 hasn't ever had one, it now needs one purely based on age. Every B3 owner has to do this its almost a rite of passage!! Yes, its a dash out job. The first time you do it it will take more than a few hours and you will find other bits and pieces to do along the way, heater flaps, wiring abortions and such like. There have been some very good how-to guides written over the years. You'll know its gone if you are constantly topping up with water, wet footwells, excessive condensation, greasy film on windscreen etc. Foam from the vents - prob a safe bet your flaps at the very least have had it I'd say Find where the lower vents are for the footwell on the passenger side, have a quick feel inside, if its wet there you have confirmed it without taking anything apart. This is where the matrix lives and is its lowest point. Good luck! __________________ -1987 90 2.2E / Sapphire Blue (Rest in Pieces) -1989 90 quattro with Sport Equipment / Satin Black -1997 A4 Avant quattro TDI 110 / Tropical Green (Sold) Last edited by Mellis46; 27-08-18 at 01:23 PM.

27-08-18, 06:50 PM	#5
Mellis46 Aero Advocate Classic Audi Club Member Join Date: Aug 2014 Location: Lancashire Posts: 1,448	Thats how they go, all at once! I feel your pain, BTDT on several occasions - you are about to embark on at least a weekend of stripping parts, drying carpets and insulation, bloody fingers and reducing your motor to a state it hasn't seen since it was being built! Good learning curve though, its a lot easier the second time round __________________ -1987 90 2.2E / Sapphire Blue (Rest in Pieces) -1989 90 quattro with Sport Equipment / Satin Black -1997 A4 Avant quattro TDI 110 / Tropical Green (Sold)

27-08-18, 08:55 PM	#6
William Blyth Grown up member Classic Audi Club Member Join Date: Jun 2018 Location: Lincolnshire Posts: 28	Whilst I'm replacing the matrix, and as foam has been blowing from the air vents; I must presume that the foam has come from the from the heater box vents ? Would that be correct ? and if so any idea of thickness of sticky backed foam required? Last edited by William Blyth; 27-08-18 at 08:59 PM.

27-08-18, 02:55 PM	#3
sinbin5t 4 ring whore! Classic Audi Club Member Join Date: Jan 2010 Location: Where a spike points skywards Posts: 12,960	As above, good advice !

27-08-18, 04:05 PM	#4
William Blyth Grown up member Classic Audi Club Member Join Date: Jun 2018 Location: Lincolnshire Posts: 28	yep! have now left car to dry overnight in garage with roof open. Felt the bottom passenger airducts and are now wet with brown bitter tasting water! strange how things suddenly start- Saturday fine and heating working ok and on Sunday heater broken!

27-08-18, 10:15 PM	#7
sjp001 Grown up member Join Date: Jan 2014 Posts: 62	I had to do this job on my b4 last winter, presumably similar to a b3? It took me all weekend to sort out, but the matrix itself is a cheap part. There is an absolutely brilliant walkthrough created by Paul Goodwin and Ian Simmonds found here: https://www.s2forum.com/articles/200...lacement-guide I bypassed the matrix for a few weeks until I had time to do it. At least this stopped the carpets getting further soaked.