Heater matrix?

[davidwort 0]

I seem to be losing a small amount of water, perhaps a cupful every 500 miles, doesn't seem to be any water leaks from any of the hoses, no deposits about, no water in the oil etc..

Could it be my heater matrix? I seem to get quite a bit of moisture on the windows inside the car but not much more than I think is due to colder weather.

The matrix is obviously not totally bust as I dont have wet feet or carpets, is there any way of checking it without removing the dash? How do these things actually fail, do they just corrode through like on a radiator, there doesn't seem to be any water leaking from the hose joint in and out?

 

ta,

David.

[gibber 0]

Have you tryed changing you cap? or at least the seals in the cap?

[RACK 0]

How hard is it to change to heater matrix? I think mine has gone teets up!

I'm only getting slightly warm air for about 45seconds then it's cold.

[Henny 0]

that's more likely to be the relief valves in the engine bay Rack, they're about £25 from VAG IIRC... 8)

[Henny 0]

davidwort, when a heater matrix fails it leaks from around the joints which hold the parts together (it's like a mini radiator, ie a core with 2 end tanks) It may just weep for a while before it finally gives up completely.

 

I reckon that the best way to test it is to bypass it in the engine bay with a piece of copper tube and see if your water leak continues...

[RACK 0]

Where abouts are the Henny?

Cheers

[Henny 0]

They're in the 2 pipes which go into the bulkhead at the back of the engine bay. Big metal/plastic lumpy thing with 2 rubber pipes going in and 2 coming out and through the bulkhead.

[RACK 0]

I had to replace one of those pipes going to the bulk head about 6months ago due to it splitting.

I'll have a look later.

Cheers mate

[davidwort 0]

davidwort, when a heater matrix fails it leaks from around the joints which hold the parts together (it's like a mini radiator, ie a core with 2 end tanks) It may just weep for a while before it finally gives up completely.

 

I reckon that the best way to test it is to bypass it in the engine bay with a piece of copper tube and see if your water leak continues...

 

Great idea, cheers very much, will try that first,

David.

[davidwort 0]

Have you tryed changing you cap? or at least the seals in the cap?

 

cap is pretty new, although it is a GSF replacement and blue rather than the VAG black one, seal looks OK and it doesn't seem to have any residue from the anti-freeze around the cap or tank, I think I'll bypass the matrix as Henny suggested and take another careful look at every pipe joint, cheers, David.

[gibber 0]

Is the temps not different on the Blue and Black caps? Blue being a lower boiling point?

[davidwort 0]

Is the temps not different on the Blue and Black caps? Blue being a lower boiling point?

 

Never heard of that one?

Wouldn't surprise me though, I mean GSF sold me a 16v radiator that was an 8v carb one just the same physical size as a 16v (less cores) :roll:

 

all the part numbers for polos, passats, corrados and golfs seem the same 1H0 121 321C for the tanks caps

 

David.

[Henny 0]

all new caps (including VAG ones) are now blue... no-one knows why though... :|

[gibber 0]

The reason I say this was my Fathers AMG Merc was having the same problem, no water leaks anywhere, water pump had been changed and tested, and still it was loosing water slowly, it ended up being the cap allowing the water to percolate.

 

Logic would say that the caps are different colours for a reason.

But then again I could be well out and talking poo!

 

Edit- Halfords ones are still black :wink:

[davidwort 0]

all new caps (including VAG ones) are now blue... no-one knows why though... :|

 

Blue = Water ???

 

Black = Oil ???

 

Makes sort of sense I guess.

 

I know a few people who I wouldn't trust to put the right stuff in the right place!

 

I can see people still getting confused between washer bottle and coolant though!

 

David.

[C. Will Corrado G60 2 0]

that's more likely to be the relief valves in the engine bay Rack, they're about £25 from VAG IIRC... 8)

 

Hi,

 

I'm having the same problems as RACK, I get hot air for around 45 seconds thenit's cold. You say it's more than likely the relief valves, where are they?

 

Is there anyway of checking?

 

Chris

[davidwort 0]

Back to my original problem (slow water loss), found the culprit, rad was changed a year or so ago and I carefully tightened the rad fan temp sensor into the bottom right (viewed from front of car), but when I checked again it had worked slightly loose after about 10,000 miles and was just weeping water, have to be careful tightening it though as it's a metal thread into the plastic part of the rad.

 

David.