Demister Troubles

[alexturner]

Hey Guys,

So I have encountered an interesting problem... Due to all the rain lately the Defender has been fogging up a little on the inside. Usually it's not a problem but now I've encountered trouble. The heater unit takes a good 10-15 to heat up and before it's warm - I can't see out the window(s). Does anyone else have this problem? Any known solutions.

I'm thinking of upgrading the heater unit buy installing a larger alternator and an element or two. Any suggestions?

https://www.aulro.com/afvb/

[rainman]

10 - 15 mins is a little long. After a 5 min warm up at 900-1000 rpm and a few mins into the drive and mine is starting to work.

The coolant is always flowing through the heater matrix. When you flick to hot, a flap in the heater box diverts the air flow through the matrix rather than around it.Maybe mark or put some tape on top of the box to indicate the position in both the full cold and the full hot position and then disconnect the cable. Move the flap (so the lever on top of the box) by hand and check and it's hitting both ends of it's travel.

Otherwise, you might be looking at a blocked matrix, so limited coolant flow. I can't say I've ever seen this problem; anyone else? They normally just leak.

[SimonM]

Gday Alex. I have the same problem I just use a cloth nappy to wipe the window, just have to make sure it is clean. Simple and it is clean.

[rainman]

:Rolling: I'd be concerned about touching any nappy that Mr Ploppy had lying around.

James

[SimonM]

:Rolling: I'd be concerned about touching any nappy that Mr Ploppy had lying around.

James
:D

Wise choice.

[dromader driver]

Check the drain on the bottom of the air inlet just before the heater box is open and working otherwise the heater turns into a kettle boiling the water which then condenses on the windscreen.

try unscrewing the air intake and you should be able to get your hand into the top of it then apply limited hosesing to flush it out.

[LowRanger]

Hey Guys,

So I have encountered an interesting problem... Due to all the rain lately the Defender has been fogging up a little on the inside. Usually it's not a problem but now I've encountered trouble. The heater unit takes a good 10-15 to heat up and before it's warm - I can't see out the window(s). Does anyone else have this problem? Any known solutions.

I'm thinking of upgrading the heater unit buy installing a larger alternator and an element or two. Any suggestions?

http://a6.sphotos.ak.fbcdn.net/hphotos-ak-snc6/284099_10150322638566203_700831202_9913143_11114_n .jpg'dl=1

Alex

If your engine temp is taking 10-15 minutes to warm up,then that is too long,and you may need to replace the thermostat.If the engine temp warms up quickly but the heater is taking 10-15 minutes,then as mentioned the 1st thing to check is that the cable adjustment at the heater box is giving you full movement.It is very common for the outer cable to slip under the clip that holds it down on the heater box and not allowing full actuation,also check the cable adjustment of the flap that directs air to the screen.If the adjustment is correct then take the ducting tube coming from the vent on the front guard to the heater box off,and make sure that the heater box is not partially full of rubbish,ie mud/leaf matter etc or water which can lay in the bottom of the heater box if the drain is blocked,and any moisture with be passed into the cabin as humidity and will fog the screen.I have had this happen in cold weather when going through deep water that can splash over the top of the guards,and before the water can drain from the heater box,the screen will instantly fog up till the water drains out completely.The other thing is that without A/C you will always have some sort of fogging issue in cold wet conditions due to the humidity in the cabin.The only time I use my A/C is to reduce the humidity in cab and help clear the screen when it is raining.And of course,if you have the standard LandRover internal water fountain,any internal water on the floor etc will add to the humidity in the cab,especially when it is being heated by a nice warm floor pan.

Wayne

[Reads90]

Go to super cheap or repco and get rainx for inside

It stops the mist you get on the inside when it rains

Not the cheapest but really works. Used to use it all the time in the Uk bit don't really need it so much in Brisbane


Sent from my iPhone

[Tusker]

Check the drain on the bottom of the air inlet just before the heater box is open and working otherwise the heater turns into a kettle boiling the water which then condenses on the windscreen.

try unscrewing the air intake and you should be able to get your hand into the top of it then apply limited hosesing to flush it out.

Thanks for this. It's been my experience - turn on the demister & the windscreen just fogs up more quickly - all that warm, moist air condensing on cold glass.

Just a Defender thing you live with.

How successful are those wingtop scoops at keeping the rain out in the first place I wonder?

Regards
Max P

[dromader driver]

I was going to get one of those ram air thingy's as the fan is stuffed again. Will just put a blanking plate in where the fan goes until I can find a japanese, holden or ford similar size one at the wreckers.

From looking at the high speed aerodynamics involved the water should hit the bottom of the inlet tube as it goes around the bend and drain out the bottom with a bit of positive pressure assistance

At least that should work below mach 1 but these defenders are tricky at high speed......

:angel:

[LowRanger]

Thanks for this. It's been my experience - turn on the demister & the windscreen just fogs up more quickly - all that warm, moist air condensing on cold glass.

Just a Defender thing you live with.

How successful are those wingtop scoops at keeping the rain out in the first place I wonder?

Regards
Max P

Max
Unfortunately all the wingtop scoops that I have seen have the scoop facing the wrong way ie. facing forward which allows the water to enter the scoops under pressure as the vehicle is driven forward.I believe the scoops should face backward and allow the negative pressure created behind the scoop to take the water away from the entrance to the ducting and limiting the water that gets into the heater box and fan motor.I have found that my Defender doesn't need any ram air effect,as the fan motor is able to supply ample air flow without scoops.

Wayne

[land864]

On the bottom of the air inlet box under the guard is a small one way rubber valve set up.
It is towards the back and under the air inlet box . Take a look from the top with a torch and I think you can see it Feel around for a small rubber fitting , squeeze it and water will come out.

It's designed to let water out but not in. Leaves , dirt etc will clog it up

[JohnF]

years ago service stations had antimisting paper they gave to customers. It was wiped on the inside of the screen and stopped it fogging up. I know about these because my dad was the printer who printed them. But I do not know how they worked or if still available,

[Tusker]

Max
Unfortunately all the wingtop scoops that I have seen have the scoop facing the wrong way ie. facing forward which allows the water to enter the scoops under pressure as the vehicle is driven forward.I believe the scoops should face backward and allow the negative pressure created behind the scoop to take the water away from the entrance to the ducting and limiting the water that gets into the heater box and fan motor.I have found that my Defender doesn't need any ram air effect,as the fan motor is able to supply ample air flow without scoops.

Wayne

Agreed

But presumably they would keep most of the rain out when stationary e.g. while parked going nowhere in Sydney's rain of the last few days.

Regards
Max P

[Tombie]

Go to super cheap or repco and get rainx for inside

It stops the mist you get on the inside when it rains

Not the cheapest but really works. Used to use it all the time in the Uk bit don't really need it so much in Brisbane


Sent from my iPhone

Agree ^^

Its called "FogX" and is worth its cost.

[rar110]

Air from the heater travels through the lower dash and then vertical to the vents. There is a piece of vacuum type hose that connects the lower dash to each vent. The hose can dislodge causing much reduced air flow to the windscreen. This might be a reason, particularly if one side is better than the other.