[filcord]

Originally Posted by ram

A harsh detergent like Surf or Ariel would eat away the wax-polish is still on the car. I use a half-cup of Pril dishwashing detergent in the windshield washer reservoir each of my cars.

Both products need to be used.
Use Surf, or any other detergent in strong solution. You must impregnate a small piece of cloth with this solution, and rub the windshield outside. Then rinse with plenty of clean water. Don't get this solution on your paint. The purpose of this is to take off all the road grime, oils, waxes, that otherwise prevent a clean wipe of the winndshield.
You must also use Pril in the washer reservoir, to deal with cleaning needs during the drive.
But the first step, pre-drive, is very important, and works like a charm. You will never face any problem with bad vision in the rains.

[saildrive]

Thanks Planet Rocker

I cant have the rear wiper fixed - also i dont have the fog lamps in place. The problem is not more in the front cos I can drive slow and reach the destination, but with the RVM which becomes insignificant as the rear windscreen is so damn blurred!

The saddest thing is that I wont be able to drive in rains despite having a car

Is there any chance that I can have a fitment done to solve this issue. I really dont want to pull over and wait for the rains to ease out, its like owning a bike (what a shame)

Also what is a fresh mode (does this mean having the blower on and switch off the AC). Does this help really.

[SmartCat]

Eventhough I have driven for 60,000 kms mostly in highways, I'm embarrassed to say that I haven't figured out a proper way to prevent fogging of the windscreen. Can somebody explain the science behind the fogging (of insides or outsides)? Then I might be able to get things right.

I always drive with the AC on, with outside air coming in, when on highways. If it starts fogging outside, then its not so bad. The wiper can take care of it and clear the windscreen. But it still affects visibility because the windows get fogged up.

So can somebody explain what should be done when -

- when it starts fogging from the outside
- when it starts fogging from the inside.

[planet_rocker]

fresh air mode: ventilation mode - use the knob/switch which allows you to use/circulate the outside air.

regarding windows (side) getting fogged - i use the 2 centre airflow vents and keep the side vents (L & R) closed - this helps a lot (but will definitely result in rear windscreen getting fogged from outside).

if the cabin / inside of glasses gets foggy - you know what to do - switch on the AC.

if the outside gets foggy (for rear / front windscreen) - use wiper + washer - helps a lot (i know that your car doesnt have the rear wiper)

@ smartcat - when its raining:

no AC - the cabin is warmer (+ humid??) than outside and hence it gets foggy inside
with AC on - the cabin is cooler (+ drier due to AC) than outside and hence it gets foggy outside.

[SmartCat]

Rocker, where should the temperature control knob be in both the scenaios (inside/outside foggin)? Blue (cold) or Red (heater) or somewhere in the middle?

[Zappo]

Originally Posted by saildrive

I cant have the rear wiper fixed - also i dont have the fog lamps in place. The problem is not more in the front cos I can drive slow and reach the destination, but with the RVM which becomes insignificant as the rear windscreen is so damn blurred!

The saddest thing is that I wont be able to drive in rains despite having a car

Is there any chance that I can have a fitment done to solve this issue. I really dont want to pull over and wait for the rains to ease out, its like owning a bike (what a shame)

Also what is a fresh mode (does this mean having the blower on and switch off the AC). Does this help really.

Rear fogging is a problem that every car owner learns to live with. Even the so called defoggers do not help at all once it starts fogging up in the rear with vengeance. But then you have to drive cautiously and the RVM will show you ghosts which still helps you in making out the vehicle behind. You may not be able to tell if it is a M800 or an Alto maybe but you will know that you have a car behind or a bike. We all learn to make do with the limited info that the RVM provides in such cases.

Fresh air mode is when you put the AC to draw the air from outside. As opposed to this when the AC is put to Recirculate mode its mostly the inside air that is being recirculated again and again. You can have either modes on whether you run the AC or just the blower.

Originally Posted by smartcat

So can somebody explain what should be done when -

- when it starts fogging from the outside
- when it starts fogging from the inside.

When it fogs from inside the best thing to do is to put the AC on. It clears up the screen in a jiffy. At least the front windscreen and both the front side windows clear up quickly.

When it fogs from outside then its a little more tricky. Mind you, the wiper will never manage to clear up this fog. The best solution I find is to roll down the windows and let the air flow inside to more or less neutralize the temperature difference. This helps to some good extent.

Good thing is that the outside fogging mostly occurs after the rain has stopped. So opening the windows is possible. When it rains the fogging mostly happens from inside.

[SmartCat]

Good thing is that the outside fogging mostly occurs after the rain has stopped.

Yes, the rain had almost stopped yesterday when it began fogging on the outside. But I never realized that this happens only when the rains have stopped

[filcord]

Originally Posted by Zappo

When it fogs from outside then its a little more tricky. Mind you, the wiper will never manage to clear up this fog. The best solution I find is to roll down the windows and let the air flow inside to more or less neutralize the temperature difference.

Fogging outside is because your glass is cold (from the interior AC) and moisture condenses on the outside of the window glass.

Simple trick : keep a/c on, but increase the temperature knob from blue towards red until you are comfortable. The a/c will still dehumidify the inside, and you don't get fogging inside, and because the air is heated, the window glass does not get too cold to cause condensation on the outside. Try it.

[santosh.s]

Originally Posted by smartcat

Eventhough I have driven for 60,000 kms mostly in highways, I'm embarrassed to say that I haven't figured out a proper way to prevent fogging of the windscreen. Can somebody explain the science behind the fogging (of insides or outsides)? Then I might be able to get things right.
......

So can somebody explain what should be done when -

- when it starts fogging from the outside
- when it starts fogging from the inside.

Flicord has already explained, but let me elaborate further:

Fogging can happen due to any of these 2 reasons- increase in humidity at a given temperature, and reduction in temperature at a given humidity level. To get around it, the idea is to reduce humidity and increase the temperature. When it rains, the atmosphere (both outside and inside of the cabin) becomes more humid along with lesser temperature. Both of which obviously have adverse effect of fogging. There is another factor to be considered for the inside region, which is occupants. They contribute a lot to increase humidity level due to respiration.

In my experience, switching on the A/C can quickly absorb the humidity inside the car. However, most people believe that A/C must be run at cool temp. setting. Because of that you make the cabin even more cool which is not desirable for fogging and makes things worser for outside surface (in addition to compromising on comfort). Therefore you should keep the A/C ON and simultaneously set temp. knob at a warm position, at max comfortable temp. Note that dehumidification of A/C is not applicable for outside air, so warming up the cabin is the only way to avoid external fogging. Try this, it works very well, keeps all glasses devoid of fogging on both sides. Contrary to the myth, it is quite safe to use car's A/C at hot temp. settings. It can't remove rain drops though

[SmartCat]

Thanks Santosh and others. Let me use this newly acquired science knowledge and see if I can get rid of the fog in seconds. Usually, I fiddle around with the knobs and it takes something like 5 minutes to find the 'right setting'.

[theexister]

Just a few days back, my car was parked outside for a long time. Meanwhile it has rained heavily & by the time I got back to driving the car the rain had stopped.
I had never seen that level of fogging on the front windscreen. I went ahead the usual practice of turning on the A/C in cold. As I was driving, the fogging got so bad that I couldn't see a thing. It was night time which made things worse. I just stopped the car on the side & got out to look at the windscreen from the outside. It was completely fogged. I took a cloth & wiped it off but common sense told me to set the temperature to warm when I turn the A/C on.

Within a few seconds of turning it to warm, everything was clear. I realize that the right balance of temperature needs to be maintained between outer & inner surface of the windows/windscreen.

[gd1418]

You get after market defogger that can be installed by any accessories guy. This shall prevent the blurring of the rear windscreen when switched on.

Originally Posted by saildrive

Thanks Planet Rocker

I cant have the rear wiper fixed - also i dont have the fog lamps in place. The problem is not more in the front cos I can drive slow and reach the destination, but with the RVM which becomes insignificant as the rear windscreen is so damn blurred!

The saddest thing is that I wont be able to drive in rains despite having a car

Is there any chance that I can have a fitment done to solve this issue. I really dont want to pull over and wait for the rains to ease out, its like owning a bike (what a shame)

Also what is a fresh mode (does this mean having the blower on and switch off the AC). Does this help really.

[gd1418]

Zappo, I would tend to disagree with you on the defogger bit. In both my trucks the defoggers ahve worked damn well to clear the blurring completely - during winters and rainy seasons as well.

It would not be out of place to mention that when I had an Esteem LX of '99 vintage it didn't have a defogger at the rear. It used to be a lot of trouble while reversing. I installed an after market defogger and ever since drove happily.

Maybe you have had a bad experience with them..!

Originally Posted by Zappo

Rear fogging is a problem that every car owner learns to live with. Even the so called defoggers do not help at all once it starts fogging up in the rear with vengeance. But then you have to drive cautiously and the RVM will show you ghosts which still helps you in making out the vehicle behind. You may not be able to tell if it is a M800 or an Alto maybe but you will know that you have a car behind or a bike. We all learn to make do with the limited info that the RVM provides in such cases.

[Vista2Swift]

The a/c works when the glass is fogged from inside. If its not working or increasing the fogging then switch off the AC and use the heater for the glass, it works . For the rear glass however there is no option but to install a after-market defogger/wiper.

[sathya_nars]

BTW, I noticed in my SX4 that rear defogger can be switched on only when headlight switch is on - weird or am I missing something?

Also, can rear defogger be used to dry out water drops after rain stopped?