MGB heater smoking (or steaming) into car

[thegman]

Does anybody out there know why my B has started to blow smoke (or might be steam) out of the heater? Any ideas whether this is just water? Turning of the heater ends this particular special effect.

Suspect it might be water that has condensed in the heater but no real idea.... It carried on for at least an hour yesterday when I just let it run trying to burn off whatever it was.... Any help much appreciated.

[MG Mark]

If it is smoke then there would be an obvious smoky smell, and I wouldn't think condensation would last that long. As it disappears when you shut the heater off, I suspect that it might be a leak that has developed in the heater matrix, which is like a small radiator inside the heater. What's happening to the coolant level when this is happening?

MG Mark

[thegman]

will check and get back to you guys tomorrow.

now that you mention it does smell like antifreeze and I just topped up the rad with afreeze.

[Mucus]

I'd agree with MG Mark, it seems to be a leak either in the heater matrix or one of the pipes at the point where it joins the matrix. If you need a new matrix you might want to consider an uprated version that is available.

[wadgebeast]

It's usually a break down in the matrix, which means you will be losing water! Keep an eye on your levels and watch your temp gauge!