Hi,

I've got a 1994 e36 318i, and am having a problem with the heater.

It normally just blows cold air, occasionally warm or hot, this is with
leaving the temp setting at MAX.

I think there's a v slight leak in the cooling system, whilst hot I can hear
a fait hissing noise near the thermostat. I'm going to have a new thermostat
and cooling flush done this week, if the heater problem continues, what
shall I try next? Could the heater valve be stuck or blocked so that no
coolant's going to the heat exchanger?

Please don't tell me its a head gasket, I've had enough of that with a Rover
K series engine in the past!

Cheers,
Nick