I'm wondering why mine demists immediately at the passenger side but not where I want it to? It's weird, there's like a square of un-demisted screen right in front of me, while the rest is perfectly clear. It clears eventually, but not before I've rubbed it which I hate doing.

Isn't it because the run to the side you need is longer therefore less efficient? Is it a downside of converting from lhd to rhd?

I think lhd only have the one demister, don't they?

Frugal Citroen, why make a second style of tubing when you can use what you've already got ... ?

The central divide favours a left hooker, so on a RHD car the passenger side nearly always clears first, I say nearly as some people remove the central deflection resulting in the middle of the screen clearing quickest.

As Louise has mentioned, on later RHD cars the driver's side demister tube is about 3 times longer than the one on the passenger side, so there's much more resistance to air flow.

Also, its design isn't very good, with 2 turns of almost 90 degrees to accommodate, so the cardboard tube is prone to collapsing.

To make matters worse, the quality of some of the replacement tubes is poor, with the foam lining not bonded to the corrugated outer tube and prone to 'bunching'.

I'm not sure what's meant by a central deflector, as the feeds to each demister nozzle are discrete, from RH and LH heat exchanger respectively...

ken

Black plastic portion internal behind dash, outer casing with a central plastic sweep, deflecting the air towards passenger side.

Louise, Mr Sf4x4 has a row of Pc fans at the top of the rear window to pull the warm air from the 2cv roof area down to demist the rear screen. Works well by all accounts...

There's something like that on Dyanes, but not on later 2CVs...

ken

Does E plate 2cv count as late ... though, maybe I used the one off the Dyane ... can't recall! Oh well, just shows Dyanes better

Ha!
no doubt Russell will be along in a while to disabuse you of that belief...

Anyway, back on topic.
I did a lot of work on a 1975 2CV in the Autumn and the owner, who's had the car since 1976, commented that the driver's demister had always been hopeless.
RHD cars from that time had only one demister, fed from the LHD type bulkhead fitting, so they had an even longer piece of cardboard tubing than later RHD cars.

Bernard suggested that some of this would work better, as long as the increased noise transmission wasn't a problem.
< http://cgi.ebay.co.uk/63mm-2-1-2-Neopre ... 1348wt_876 >

He'd bought a full set of Michelin M&S tyres for the car in early December, so I'd guess he's been giving it a good test.
Will be interesting to hear how the tubing has worked...

ken

Yeah, I'm tempted to start banning anybody who starts this pro-dyane nonsense.

As for heating? Put a coat on or buy a modern car.