Fogging Up Spectacularly

[CatfishCKY]

Hi guys
over the past week or so, my mk1 has been fogging up really badly - i've never seen it this bad and I've had the car 18 months now. It's to the point of being dangerous, and nothing is clearing it
All the windows, including the rear screen are fogging up badly (plastic window), and even with the demister on full blast, it only manages to keep the windscreen half clear, and i have to keep wiping the side windows whilst driving I would have tried leaving the windows down today, but obviously it has been raining cats and dogs! I did have it down for the morning at work, and the windows were clear when I left, but that soon changed!
I have put a dehumidifying egg in there, and will see how that goes, but does anyone else has any other ideas?
I've not had the issue before, the fans are working fine in the sense they are kicking out plenty of air; cleaning the windows only works temporarily; and carpets are not wet. There is a slight crack in the corner of the windscreen, but it has never been an issue before - though admittedly it has been there the whole time I've had the car, so maybe my luck has ran out!
Anyone experienced the same?

[PATTERNPART]

That's annoying as we have a few months of rain to look forward to. I sympathise. There must be moisture inside which when the car warms up is turning to vapour and condensing on the cold glass. If you had aircon that would clear things up quickly but not cure the underlying cause. Try looking at the trim on the shelf behind the seats. Have a really good delve as I suspect that the drains for water running down the back of the roof may be blocked. Water would creep down behind the seatbelts etc. There are reams of information all over the place about cleaning blockages out of these tubes. Then leave your windows open as often as possible on sunny days.

[HaylingJag]

without wanting to state the obvious, but you havent switched to air recirc have you?

D

[mx5alan]

2 things to check

1: Check the drain holes in the rocker panels are clear. These are located under the car behind the sills either side of the doors.

2: Check the drain holes in the flat panels at the foot of the seat-belt securing points near where the roof folds - This is where all the water goes from between the roof and the bodywork. There are plastic tubes which drains the water away and out just in front of the rear wheels.

Over time these can get blocked up which can result in your misting up problem

[CatfishCKY]

hi guys, thanks for the responses so far.
Sorry, forgot to mention though might be obvious, I don't have aircon in my car, but I know that would help immensely if I did!
I haven't got recirc on, no. Checked and it is the right fresh air setting - haven't had it on recirc for a few months now, so hopefully it hasn't jammed or anything!
I do need to check the drain holes, but it has been peeing down all day so haven't been able to check. I will try and check tomorrow if I can! Roof is usually watertight, so am not worried about that, but will check for wet patches tomorrow. If the weather is good!

[shogun001]

Leaking heater matrix?

[CatfishCKY]

good shout, how would I check for sure?

[rovermorris999]

You'd smell the antifreeze if it was. Unless the pink stuff doesn't smell.

[Oldandslow]

I'd look at your coolant level and see if it's dropped. Top it up and see if it drops again. Check if it's got antifreeze in it. If it's a good blue(red/pink NOT rust ) colour and you can't smell it in the cockpit I'd be very surprised if it's the heater matrix.

Keep looking for signs of damp carpet or trim. There are several areas leaks can come from and they can depend on how the car is parked i.e. facing upslope/downslope. If all else fails, sit in it like a lonely nutter during a rain storm and look for drips (voice of sad experience).

[shogun001]

Dropping coolant level is the main symptom. However don't forget there may be water collecting behind/underneath the carpet as it being waterproof works both ways.

Does the screen clear clean or is there a residue left behind when it's evaporated away?

[HorneyMX5]

Start lifting the carpets, mine did this and the soudproofing under the carpets was soaked.

[CatfishCKY]

I can check coolant no problem, will do it before i leave today. I have checked the carpets before, but no harm in doing it again.
I'm not sure if it leaves residue once cleared as i have been using screen wipes to clear it eventually. That leaves a little residue! I might get the car valeted this weekend, get them to clean the screen and hoover the carpets, then go from there :-\

[Planet Claire]

Another thing to try, possibly, is search ebay for bags of silica gel (they're quite cheap). I don't mean those 1" sized sachets that you sometimes find in leather bags etc, but bigger bags of the stuff. An ex-boyfriend of mine used to keep a large bag of silica gel under the seat of his MR2 to stop the condensation - it was so long ago I can't remember whether it worked or not, but in theory it should! The bag size he had was something like 8"x4".

[rovermorris999]

Try these or something similar

http://www.amazon.co.uk/gp/product/B0017RO0OW?*Ver...

[MX-5 Lazza]

Another place to check for water is in the boot, again under the "carpet" and in the well.

[CatfishCKY]

Well, yesterday was interesting - i have had the dehumidifying egg in there since i got them and yesterday it didnt fog up once on the way to and from work. All 130 plus miles. I had the window open most the way too, and it seemed fine.
I did check coolant and it was pretty low, halfway between full and low. So that has gone down because my dad topped it up recently.
Yesterday evening i went to tesco and it started misting up again as it began to rain, and i did get a whiff of coolant this time :-( looks like the heater matrix could be to blame...
Is it worth taking it to a garage to get it done?

[snotrag]

Its not too hard. A lengthy job, fiddly, and ideally you'll want to be inside, but its very DIYable and will cost a fortune at a garage simply due to the length of time it will take.

Basically - seats out, centre console out, steering wheel off, undo dash, disconnect all the wiring, pull dash out, replace matrix. While its out you may as well pull all the carpet out and make sure its all dry.

[DEKE]

Hi There

You could try K Seal does what it says on the tin, I have used this on a V8 TVR and it worked with no issues at all, I would think worth doing before any thing else do not use any other. You can get it online or from good accessory shops.

[shogun001]

Please don't..... It's not a fix.... There is a UV dye you can put in the coolant if you wanted to be doubly sure before stripping the dash out.

It's easily done in a day but gets much easier with practice.

[Vin]

mine has started fogging on the windows. i will also check those tips. thanks all