Clogged heater matrix help. Thread name changed.

[AudiA8Quattro]

How can it be clogged if I have run water through it ok?
What is inside the matrix? Is it just a pipe weaving left to right all the way down and back up with fins on it or does it have chambers?

If the matrix is clogged internally it can still flow properly, but there won't be enough heat transfer.
This is what happened on my old polo, exactly the symptoms you describe, i removed it, flushed it, it flowed perfectly.
In the end a new matrix cured the problem. An easy job on an old polo though..

[stainesy]

So if it was a clogged matrix on your polo why didn't you flush it out?

[justalex81]

i think the cable has snapped that changes from hot to cold air

[AudiA8Quattro]

So if it was a clogged matrix on your polo why didn't you flush it out?

I said i did flush it in my last post 
Unfortunately it only made a slight improvement, so i replaced the matrix.
Easy job on a 1993 Polo.

[Seanl]

Right mate, here we have 1 x 21 year old heater matrix.












Here we have the end cap off, so you can see the waterways from the outside.










And here we have it sawn in half with a wood saw!












Crap pics with camera phone, but u get the idea. Here is a close up of the waterways.












As you may be able to see, every waterway has hard limescale blocking it the varying degrees. I flushed this through and did get water back out, and both pipes were hot. There just obviously wasn't enough in there through all the sh!te to ensure decent heat transfer.
Hope this helps mate. 

[stainesy]

Mate ou are a fcuking legand 
I can't belive you actuly cut that in half to show me  your a diamond geezer cheers fella.
So it realy is just a single pipe that goes up and down up and down up and down and up and back out. So it has to be a clogged matrix.
Ok great what do you guys recon I should try on this then?

Coolant flush? Lime scale remover? Jet wash through it?

[Santiago]

Mate ou are a fcuking legand 
I can't belive you actuly cut that in half to show me  your a diamond geezer cheers fella.
So it realy is just a single pipe that goes up and down up and down up and down and up and back out. So it has to be a clogged matrix.
Ok great what do you guys recon I should try on this then?

Coolant flush? Lime scale remover? Jet wash through it?

No, it's 8 separate parallel pipes, each of which has a spiral plastic feature (not limescale) inside it to aid transfer of the coolant heat to the tube walls.  There may be some sludge in there too, but those plastic bits (like pasta spirals) are meant to be there.

[Wayne]

Jet wash through it?

I would not recommend that you stand a chance of blowing the matrix apart, coolant flush may help.

[Seanl]

Mate ou are a fcuking legand 
I can't belive you actuly cut that in half to show me  your a diamond geezer cheers fella.
So it realy is just a single pipe that goes up and down up and down up and down and up and back out. So it has to be a clogged matrix.
Ok great what do you guys recon I should try on this then?

Coolant flush? Lime scale remover? Jet wash through it?

No, it's 8 separate parallel pipes, each of which has a spiral plastic feature (not limescale) inside it to aid transfer of the coolant heat to the tube walls.  There may be some sludge in there too, but those plastic bits (like pasta spirals) are meant to be there.

It does look like parallel pipes looking at the pics now actually. 

These spiral plastic bits then, if they are meant to be there, were extremely brittle, They felt like blocks of limescale and fell apart when rubbed between my fingers into tiny grit like particles. If these collapse then I reckon they could cause blockages on their own. Either way, it was blocked, and now a new matrix has sorted my problem out. 

No worries Stainsy! It was the old one and sat in the shed anyway! 

[stainesy]

Bet you havin cutting that in half realy didn't you 
Ok looking at the history of the car. It has had a new head gasket about 10k miles ago and the coolant looks dirty brown so I am going to flush it. Should I use forte coolant flush or forte bio degreaser?
The flush says it get rid of rust and lime scale but not sludge and the bio degreaser says it gets ridge of congealed oil and sludge. What ou recon?