4 replies to this topic

[bobbym18]

Hi all, 

 

I recently replaced my heater valve at the same time as i replaced the head. I had a few problems with leaking radiator hoses but i seem to have sorted that.

The problem I have now is, smoke/exhaust fumes/water vapour coming through the air vents along the windscreen after the engine has been running for a few minutes.

 

I just want to see what you guys think, is this just where the valve is new? or is it too hot? or something more serious? Whatever it is coming out carries on for a while after the engine is turned off so it is obviously related to the engine being being hot/warm.

 

Any suggestions would be appreciated.

 

Thanks

 

Rob 

[RedRuby]

I think one possibility could be the heater matrix, I had steam through the demister vents when my matrix was leaking. Perhaps as you have drained and topped up the coolant system it has removed build up in the matrix and exposed a weakness there.

[AVV IT]

As above, sounds like a leaking heater matrix. Have you noticed your carpets getting damp/wet, or your coolant level dropping at all? I'd be inclined to drain the cooling system and extract the matrix from the heater casing to see what's going on in there. It is possible to do this with the heater still in situ in the car, but to be honest, once the matrix starts leaking, it tends to make a right mess inside the heater casing, so it's probably worth just removing the entire heater unit and giving it a strip down/overhaul if necessary.

[bobbym18]

I did have one large noticeable leak last year but it stopped the same day and then nothing since. Is it a major job removing and overhauling?

[AVV IT]

Sounds like that might be the culprit then. The matrix is one of the lowest points in the cooling system, meaning it's where all the gunge & debris tends to collect & settle. This gunge can sometimes block & seal over any holes that appear in the matrix, effectively making leaks suddenly resolve themselves. I'll see if I can dig out the photo of one of mine, that had clearly been leaking away silently in there for months upon end. I didn't even realise it had been leaking, I just noticed one day that my demisters seemed to be doing more "misting" than actual de-misting. When I stripped the heater down, the matrix looked like it had been brought up from the bottom of the sea!

Stripping the heater down can be a bit fiddly, but really isn't too difficult. It's just a case of draining the cooling system, removing the inlet/outlet hoses & then the heater from the car (two screws hold it into the lower dash rail at the front & two nuts hold it onto it's mounting bracket at the rear). If you then disconnect the earth & feed wires, you can lift the whole unit out of the car. Then it's just a couple of screws to extract the matrix from the casing. If you need to get inside the casing to clean up /repaint etc, then you just need to remove the series of small screws around one side/edge of the casing, you can then remove the blower unit from inside, as it's only held in place by three screws. If you need to use the car whilst you've got the heater out and stripped down/in bits, then as a temporary measure you can always join the heater inlet/outlet hoses together with a small length of 15mm copper pipe, (i.e plumbing/central heating pipe) so that you can refill the cooling system, and use the car, obviously you won't have a heater or demisters though.