Window condensation

[biggles]

Hello,

In light of the current "ECU problem" thread I had a related question:

When the weather is damp and cold the windscreen gets foggy when the car is started (and thus the A/C). The mist typically clears in less than a minute. Under the same circumstances there is usually some mist present on the inside of the rear screen (lower part, close to the parcel shelf vent). On a few occasions there has been some condensation on the lower part of the wind screen as well before the car is start.

Before I entered the Rover 75 domain and spent far to much time browsing forums like this :) I would probably have thought this as completely normal but... is it really? I have owned this car for less than a month but I have a faint memory of the windscreen of my "old" 75 fogging up on A/C startup back in 2000 but I might be suffering from what we pilots refer to as "confirmation bias" in this case.

My plenum was thoroughly scrutinized and cleaned of any leaves as soon as I bought there and there was nothing to clean out really. Same thing goes for the boot (dry as a bone) but I will check out the gaskets of the rear lamps some time.

The car is parked in a garage and has at most been drizzled on under my ownership.

So, am I just being paranoid or should I investigate something? As not really being a car expert but having fair engineering skills I could think of the following causes:

* Residual condensation in the AC condenser. Is there a separate drain for the condenser that might need attention by the way?

* Condensation just anywhere in the ventilation system due to, well, humid weather.

* Pollen filter getting damp no matter what due to its location.

* As far as the rear window is concerned it could be a matter of the boot being a container of warm moist air that cools slower than the window thus rising and condensation on the window.

* Leak(s).

[Pete]

Mine has always had the same problem, although one thing I do is run the a/c on cold for two minute once a week to keep it alert and that does seem to reduce the amount of condensation. I have also had it on several other makes though so I just accept it to be honest.

[Ken]

All of my cars have done this and its perfectly normal as far as I know.:lol:

Ken

[GreyGhost]

Warm car interior, very cold A/C pipes. When you switch off water vapour in the warm air naturally condenses in the cool A/C system.
Cosequently when you start the engine warmish air is pumped through the system. Condensation in pipes turns back to water vapour and is pumped straight out to immediately condense on the winscreen and everywhere else but is really only noticable on the glass.

Apologies for the waffle but this is perfectly normal. If you want to avoid it. Turn off aircon before switch off and run the heater flat out for a minute or so to warm yer pipes.

[biggles]

Warm car interior, very cold A/C pipes. When you switch off water vapour in the warm air naturally condenses in the cool A/C system.
Cosequently when you start the engine warmish air is pumped through the system. Condensation in pipes turns back to water vapour and is pumped straight out to immediately condense on the winscreen and everywhere else but is really only noticable on the glass.

Apologies for the waffle but this is perfectly normal. If you want to avoid it. Turn off aircon before switch off and run the heater flat out for a minute or so to warm yer pipes.

That's what I thought too. But considering that the 75 appears to be a bit prone to various water leaks I thought I'd check first.

So far only there is one typical 75 issue that has raised its ugly head so far and that is a lazy central locking - on two doors. Previous owner swears of course that he never had any problems with that - rrright...

Thanks everybody!

/Erik