Con very hot on intial turn on

[V8Dom]

Just wondering why aircon is blisteringly hot when first turned on. Make window fog within 2 seconds almost dangerous to drive

[Steve_D]

I would suspect your heater valve is not fully closed.

Steve

[Storer]

Steve_D said:

I would suspect your heater valve is not fully closed.

Steve

+1

Paul

[F.C.]

+1, Super common problem, Also check you have the "H" section bypass fitted to the heater pipes in the engine bay where they disappear into the bulkhead.
If this is not present the heater valve will be under constant pressure and will let by more easily.

[Ultimike]

Mine also provides a blast of hot air. Until the cold air comes through but it is only for a second or two. I always thought it was a characteristic of the car.

[F.C.]

Ultimike said:

Mine also provides a blast of hot air. Until the cold air comes through but it is only for a second or two. I always thought it was a characteristic of the car.

It is I guess but only because the heater valve is letting by and heating up the matrix, the best solution it seems is fitting an electric valve like this:

https://www.summitracing.com/int/parts/vta-50507-v...

[Storer]

F.C. said:

Ultimike said:

Mine also provides a blast of hot air. Until the cold air comes through but it is only for a second or two. I always thought it was a characteristic of the car.

It is I guess but only because the heater valve is letting by and heating up the matrix, the best solution it seems is fitting an electric valve like this:

https://www.summitracing.com/int/parts/vta-50507-v...

I fitted that to my car. Works well.


Paul

[Ultimike]

Does this issue cause any consequential damage over time as I don't have any issues with the second or two of hot air before the cold air comes in?

[Storer]

Ultimike said:

Does this issue cause any consequential damage over time as I don't have any issues with the second or two of hot air before the cold air comes in?

I suspect your aircon would be more effective if you cure the bleed by.

It has a small amount of heat to overcome before it gives you cool air.

I think there is a bit of heat bleeding back through the heater return hose too.



Paul

[V8Dom]

yes my heater is adjusted to cold..its always cold as never needed a heater on the car only aircon
it has always been the case and like Mike thought its the design of the car
if aircon is off, vent on dash is open, there seems a small misting on the screen arround the vent, and feels small amount of warm air even though heater off, heater on cold.

i dont turn on aircon alot as battery/alternator cant take it and voltage drops below 12v

when i do turn it on, there is a sudden stream of hot air which mists the whole windscreen within 2 seconds and means you are blind. its so dangerous!!

the only way to over come it is while driving , close the vents on the dash, turn on aircon low blower with knee vents open, allow hot air to escape, the reach over while driving to open the vents on the dash.. again , not the safest reaching over to the passenger side vent.