I've Google it and searched in here and yes there are opinions, but no one has ever reported back as to what the issue was resolved as being.

My fabia is always cold when not under load. And isn't really hot hot when driving either but you can put your hand on the blowers and feel them get colder as you slow down to the point of outside temperature blowing in while stationary.

I've checked the water pump is pumping I have a good flow back to the header tank.

I've had the system bled up as best I could pumped the hoses and had no further air from them

I've removed the pipes from the heater matrix and blown though to check for any blockages then refit re bled and no joy

None of these have effected it at all.

The water isn't very nice at all. Rather brown so will be getting changed Tuesday with proper red coolant and a new stat. Any other culprits for the colour that would benefit a change?

And what else is their that would cause my fault?

Thanks

Sean

What Fabia you got Sean?

Vrs 07 plate blt engine

I've normally had that issue when the water pump is knackered. Has it been replaced or not?

I know you've taken the pipes off the matrix to check is flows but it might not be going across the full matrix. May be worth taking them off and filling it direct with hot water and see if it blows hot.

It's Richard from college btw! Good luck.

Did wonder Hahah! It will blow hot if your driving just when you stop it won't! I'm getting coolant flow back into the header tank so wouldn't have thought it was my water pump either?

Matrix is probably partly sludged up. Brown coolant suggests it's been neglected in terms of coolant maintenance.

 

Although there's a 20mm pipe going in and out, the actual pipes inside the matrix are lots of much smaller pipes that all branch out in parallel. 

A bit like this:

 

Just blowing through it will only prove that not all of the little pipes are completely blocked.  You need to hook up a hosepipe to the return pipe and hit it with lots of flow at mains water pressure for a few minutes. This might shift some sludge out of some of the little pipes that may not be flowing at all, and improve heating at low coolant flow rates.