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Strange climatronic fault!

mrowell

Newbie
Oct 17, 2005
15
0
A couple of weeks ago I ran the car to warm the interior up before going to work. Bit surprised to find the interior still icy cold even though the engine was up to temperature. Even stranger was the fact that as soon as the car was rolling hot air poured out of the heater! The climatronic works perfectly OK normally but no matter what I set the climatronic controls to it will not heat the car when started from cold and left to idle - the fan blasts cold air from every orifice. Any ideas?
 

Nath.

The Gentlemans Express
Jan 1, 2006
8,620
16
EASTLEIGH, HAMPSHIRE
If it's a diesel that's pretty normal

Diesel doesn't produce as much heat from it's combustion as petrol does.

Interesting note:- I drive a diesel for work and last week in the snow It took me half an hour to get to the motorway driving the back streets in second gear at tickover revs. My heating was blowing cold the hole time until I got on the motorway, then the heat came.

It is a well known fact that a diesel engine takes longer than an equivalent petrol to warm up, Also they can sit ticking over for ages in the morning and never blow warm air from the heater.
 
Last edited:
Sep 29, 2008
835
1
Bradford
thermostat springs to mind, this closes in order for the water in the engine to heat up, when it reaches a particular temperature the thermostat opens and then lets the hot water circulate around the engine and into the heater matrix, allowing hot air to pass through the air vents, ive noticed this a few times on my father in laws A4, no matter what temp is showing on the engine temp display it will not blow hot air until he has revved the engine a bit to get the water circulating, hope this helps.
 

mrowell

Newbie
Oct 17, 2005
15
0
I've got a nice yellow 55 reg. petrol Fr! Just tried an experiment - ran the engine up to temperature - still freezing cold. I live on a hill so I ran the car down the hill at idle - still cold but when I put the car into gear and the revs hit 2000 - lots of warm air. Could be an air lock then.
 

cheshire cat

Full Member
Dec 28, 2002
1,813
1
cheshire
Visit site
thermostat springs to mind, this closes in order for the water in the engine to heat up, when it reaches a particular temperature the thermostat opens and then lets the hot water circulate around the engine and into the heater matrix, allowing hot air to pass through the air vents, ive noticed this a few times on my father in laws A4, no matter what temp is showing on the engine temp display it will not blow hot air until he has revved the engine a bit to get the water circulating, hope this helps.
the heater doesn't rely on the 'stat to work only the cooling rad:)
 

RUM4MO

Active Member
Jun 4, 2008
7,963
1,058
South Scotland
the heater doesn't rely on the 'stat to work only the cooling rad:)

Exactly, the thermostat just controls when the water is allowed to get out into the radiator leg for cooling to take place.

I think that you would really need to feel a lot of pipework to work out what is happening, as one thing you don't need is poor water circulation caused either by air-locks or a dodgy water pump impellor,, that will not be very handy for your engine - if that is the real problem.
 

mrowell

Newbie
Oct 17, 2005
15
0
Just an update. It was an airlock, though how that much air got in there is a mystery as I haven't lost any coolant!
 

RUM4MO

Active Member
Jun 4, 2008
7,963
1,058
South Scotland
Just an update. It was an airlock, though how that much air got in there is a mystery as I haven't lost any coolant!

Has this car been taken to bits since it was built up at the factory - ie new water pump? If so then I'd reckon that was when this air lock "happened". Its strange though as I'd expect some of these engines to "self purge" any air once the engine revs were raised a bit - the the liquid level would drop.

I hope that you now find that this does not happen again or there must be a real reason - ie problem that is causing this.
 
Last edited:

RUM4MO

Active Member
Jun 4, 2008
7,963
1,058
South Scotland
could be the dreaded water pump impeller on it's way.

Yes, I thought that I would just take the "soft" approach and just loosely hint that it might come to this.

To the OP, if this happens again then I'd definately get it (as stated above - the water pump) checked out. What is your present mileage and do you have an extended warranty - and have you just bought this car - or has it always done this (sorry lots of questions!)?
 
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