Question : MY Myvi is about two and a half
years old. After a year of purchasing
it, cold steam came out from the ventilation grill.
I took the car to the workshop twice
for a complete air-cond service.
The first workshop told me that
my cooling coil was dirty and after
completing the servicing, he fixed an
air filter before the air intake to the
cooling coil. However, this drastically
reduced the amount of air coming out
of the air vent.
The workshop mechanic also suspected that somehow the warmer
outside air had mixed with the cooler
air, resulting in steam.
However, he can't detect any leak
and the air-cond gas level was OK.
After a week, the problem reoccurred. A drive from Damansara to Pu-chong was enough to create steam.
So I took the car to another work-
shop. After a complete check, the
workshop mechanic told me that the
thermostat was faulty and in order
to prevent freezing, he decided to
install the thermostat a further bit
away from the cooling coil. This time
it worked but the compressor cut in
and out often.
Eight months after that, the steam
came out again.
When I asked around, the workshop
told me that it is a common problem
for the Myvi.
What am I supposed to do as every
time when steam comes out from the
ventilation, it is so frustrating and affects my driving concentration?
What is coming out of the vent is not
steam but 'fog', i.e. condensed water vapour caused by the very low temperature
in the evaporator.
There are two components in the air-conditioning system that always cause
1. The thermostat -- which controls the
compressor and which cuts it in and out
at a pre-set temperature.
2. The expansion valve -- which allows
the liquefied refrigerant to expand in the
evaporator and so give you the cooling
The usual problem is that the expansion valve is not adjusted correctly or
malfunctioning such that the flow is too
high, resulting in the temperature dropping below zero degree C in the evaporator.
This causes the water vapour in the air
flowing past the evaporator fins to start
to freeze, giving the 'fog' effect and also
smell like the freezer of a refrigerator.
If this continues, the evaporator may
freeze up completely and there will be no
air flow and ice will be seen on the evaporator fins. The solution is to replace the
expansion valve if it cannot be adjusted.
The thermostat could also be at fault
if it stays on for too long but if it is replaced and the problem still occurs, then
the cause is most probably the expansion