Ford Mondeo II (1996 - 2000) - 99 2.0 Windscreen misting up

Honest John Back Room » Technical matters
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Fri 5 Sep 2008 17:13
99 2.0 Windscreen misting up - Whacko
Uh Oh Windscreen just started to mist up, de-mister heater setting won't clear it, only aircon, and at the end of a 3 mile run in average traffic the engine fan came on, this was a new noise, I don't remember hearing it before, 122,000 miles. Any frightening diagnosis anyone ? Advice would be much appreciated.
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Fri 5 Sep 2008 17:42
99 2.0 Windscreen misting up - Screwloose

Before worrying too much; check the coolant level?

Any odd odours from the heater? Was this the first time that you'd used it this year?
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Fri 5 Sep 2008 19:48
99 2.0 Windscreen misting up - Whacko
Coolant level normal hot and cold. The heater had not been used for weeks until about 2 days ago and yes, there was a 'heater smell' to start with.
snipquote

Edited by Dynamic Dave on 05/09/2008 at 19:54

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Fri 5 Sep 2008 19:53
99 2.0 Windscreen misting up - Screwloose

Maybe a slight heater matrix weep? Probably best to see how it goes.
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Fri 5 Sep 2008 20:05
99 2.0 Windscreen misting up - jc2
Engine fan should come on if a/c on.
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Fri 5 Sep 2008 21:29
99 2.0 Windscreen misting up - Whacko
Okay thanks for that. Is replacing the heater matrix expensive ?

Edited by Whacko on 05/09/2008 at 21:30

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Fri 5 Sep 2008 22:25
99 2.0 Windscreen misting up - elekie&a/c doctor
The a/c needs to be switched on to demist the screen effectively(on some models the a/c is automatically engaged when demist is selected).Heater matrix on these rarely leak and if reqd it is not a major job,around 1.5 hours.I would suggest that the cabin/pollen filter be checked/replaced and also the a/c condensate drain tube at the bottom of the bulkhead in the engine bay checked for blockage.hth
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Sat 6 Sep 2008 11:56
99 2.0 Windscreen misting up - Galad
>I would suggest that the cabin/pollen filter be checked/replaced>

I had an Astra F that suffered from similar symptoms. Turned out the pollen filter was soaking wet caused by my over-zealous use of the hose when washing the car. Had to replace the filter as it wouldn't dry out and the car was constantly filling up with condensation.

Problem reoccurred serveral times after periods of very heavy rain: design fault apparently with the polllen filter located too close to water run-off areas. Ended up ditching the filter altogether. Saved myself £20 a throw.
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