How long to blow hot air?

Tester01

Active Member
Oct 24, 2022
110
13
Let me preface this I know cars will take a while to warm up and when driven will warm up much quicker.

Something I noticed last year and again quite recently when he had the really cold icy weather in November.

My car takes ages to defrost on winter mornings and to blow hot air to warm cabin up.

For example if I was to start engine and leave running idle I’m scraping ice of the car.
Even after say 10 minutes the car is still blowing ice cold air…Making it harder and longer for car to defrost.

A lot of the time I have to start driving for a few minutes before I get any kind of heat from the blowers.

Which isn’t ideal as the visibility from the windscreen is poor as it’s still iced and misted, but only way I can get the car blow hot/warm air.

looking around online this doesn’t seem normal or is it?
Is there anything I can check some say coolant, thermostat, radiator hose?

Or am I just overthinking?
 
Last edited:

mty12345

Active Member
Jun 17, 2011
3,956
576
bristol
Could be the thermostat stuck open, but if it gets up to temp quickly and stays there when driving, probably ok. Leave the heater off or on cold until it has some engine temp. If you put it on hot straight away, at idle the engine will never warm up. Raising the revs will also help a lot.

Get a squeege from amazon to deal with condensation until it's warm, that's what i do (i start work at 5am) and works great.
 

Tester01

Active Member
Oct 24, 2022
110
13
Leave the heater off or on cold until it has some engine temp. If you put it on hot straight away, at idle the engine will never warm up. Raising the revs will also help a lot.

Get a squeege from amazon to deal with condensation until it's warm.
Usually my heater temp stays around 20-23c, not even going to max.

So on cold mornings if I’m trying to defrost car quick as possible I should turn it right down to cold?

Just seems a bit odd that even after 10-15 minutes of engine running, still blowing ice cold air.
As I said I understand cars will heat up much quicker when driven, but I would’ve thought there would be a bit of heat at least.
 

mty12345

Active Member
Jun 17, 2011
3,956
576
bristol
Usually my heater temp stays around 20-23c, not even going to max.

So on cold mornings if I’m trying to defrost car quick as possible I should turn it right down to cold?

Just seems a bit odd that even after 10-15 minutes of engine running, still blowing ice cold air.
As I said I understand cars will heat up much quicker when driven, but I would’ve thought there would be a bit of heat at least.

It's because when you have the heater running, even at 20C, the very little heat that is being produced is immediately lost to the cold air, so the coolant never gets warm. If you leave it running without the fans on for 5 mins, you should find it builds enough heat to make a difference. I know it sounds counter intuitive, but it does work.
 

Compo1

Active Member
Jul 19, 2010
290
66
Do you eventually have good heat coming through ?

If you do it could well be the heater support pump which has the job of pumping coolant around the heater matrix until the thermosat open at that point the mechanical pump takes over.
 
May 1, 2024
2
1
And I'd suggest one of those silver coloured insulated screen covers. I got a couple from Aldi a few years back. At least it stops the ice problem.
 
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Let me preface this I know cars will take a while to warm up and when driven will warm up much quicker.

Something I noticed last year and again quite recently when he had the really cold icy weather in November.

My car takes ages to defrost on winter mornings and to blow hot air to warm cabin up.

For example if I was to start engine and leave running idle I’m scraping ice of the car.
Even after say 10 minutes the car is still blowing ice cold air…Making it harder and longer for car to defrost.

A lot of the time I have to start driving for a few minutes before I get any kind of heat from the blowers.

Which isn’t ideal as the visibility from the windscreen is poor as it’s still iced and misted, but only way I can get the car blow hot/warm air.

looking around online this doesn’t seem normal or is it?
Is there anything I can check some say coolant, thermostat, radiator hose?

Or am I just overthinking?

What engine do you have? The diesels do take a while to warm up when not fitted with an electric auxiliary heater
 

Tester01

Active Member
Oct 24, 2022
110
13
Do you eventually have good heat coming through ?

If you do it could well be the heater support pump which has the job of pumping coolant around the heater matrix until the thermosat open at that point the mechanical pump takes over.
Yeah after I start driving heat seems fine, not noticed any issues there.
 

Mr Pig

Active Member
Jun 17, 2015
2,745
983
To defrost the car you're supposed to run the air-con but I don't. The problem with that is that as soon as you switch the air-con off, the moisture collected in the pipes comes out of the vents and condenses on the windows.

I turn all the air to the windows, heater and blow up full, reticulation on and go back into the house ;0)
 
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