Screenwash Anti-freezing Mod

[mat_fenwick]

Whilst driving to work this morning (around -3°C) I suffered the common freezing up of the spray bar. I'm not too sure of the concentration but have been topping it up with neat screenwash since I got it in September, so even if it was just water previously it must be around 50% now. As it was fine before I set off, I'm wondering whether the screenwash evaporates in the spray bar first, leaving mainly water behind which freezes (wind chill I believe only applies to heated objects).

I know you can get heater washer jets, but wondered if there was an easy retro fit for the BX. And then it struck me - why not run a very fine resistance wire through the water pipe and earth it via the wiper arm (I would assume there's still a reasonable path to earth). We have a fair bit of thermocouple wire here at work, so with a bit of playing around to get the length & diameter right for the power dissipation needed, it might just work!

Whether I get round to it before summer is another matter.....

[Way2go]

Sounds a good plan..........except it probably would burn through the plastic where it touched. Getting the current right so it didn't may prove too low to heat the water sufficiently.

May be sufficient (& quicker) to attach two wirewound resistors to the wiper arm to impart heating across the air gap to the spray bar if the freezing is occurring locally. Easy enough to run some flex out of the grill and ty-rap to the arm fed from a current limiting circuit of either simple or sophisticated design?

[mat_fenwick]

probably would burn through the plastic where it touched. Getting the current right so it didn't may prove too low to heat the water sufficiently.

Hopefully not - I've got a similar arrangement at home heating about 2 metres of (larger diameter) wire which dissipates 60w @ 19V and prevents a 15mm pipe from freezing. It's warm to the touch but not uncomfortably so. A shorter and smaller diameter wire would have less resistance, so would need less voltage to dissipate the same power. So long as it needs less then 12V the wiring should be simple, just whether feeding it through the pipe & spindle will restrict the flow too much?

[Mike E (uk)]

http://www.farnell.com/datasheets/530666.pdf

8W per meter, sounds like the system used on Vauxhall Senators to stop the spray freezing.

You will need an inverter, but 16W would probably be plenty and I dont think you would melt the pipe.Just fix it to the pipe with cable ties

You could have it switch on with the rear screen demister.

Only problem is, won't the spray still freeze when it hits the cold windscreen when you get -10 in Snowdonia?

Mike

[electrokid]

We have a fair bit of thermocouple wire here at work

Stainless steel has a resistivity over 50x higher than copper and can be very useful for heating elements where corrosion might be an issue.

http://wires.co.uk/acatalog/ss.html

[Defender110]

You could easily make it so it only earths towards the end of the wiper spindle travel so it is doesn't need to be a constant feed, just enough to stop the water freezing.

You could also make a replacement wiper bar out of metal (brake pipe or similar) that you could use instead of an element wire inside plastic pipe?

[Mickey taker]

not one for the "it must be origional "brigade
but as the washer jet spray bar is a bit of an achilles heel anyway on the BX, why not get heated washer jet nozzles mounted in the bonnet , My mk2 golf has then as standard so I guess other cars must have had them too.

had a look on ebay, lots of fords have them or if you want to go a bit upmarket

http://www.ebay.co.uk/itm/Mercedes-190- ... 56485d0c71

on the golf they are linked in with the heated rear window switch

[Way2go]

I was driving behind some silly sod in a golf tonight who obviously had his nozzles adjusted for when he was travelling at higher speeds 'cos each time he operated his washers it sprayed above his roof so us cars behind got the wash.

At least with the Bx Spraybar design, you get your screenwash on your own screen no matter what your roadspeed.

[Defender110]

I was driving behind some silly sod in a golf tonight who obviously had his nozzles adjusted for when he was travelling at higher speeds 'cos each time he operated his washers it sprayed above his roof so us cars behind got the wash.

This tactic does negate the need for a spray bar modification though

[NeilGP]

Thought:
How about getting some stainless steel pipe, using a brake pipe bender to fabricate a spray bar from this pipe. Drill some pin holes for the spray and terminate each end to a power feed via resistor.

This gives two benefits, a spray bar and internal heater to stop freezing.

[Jaba]

Its almost always minus temps here in the winter. I never have freezing or screenwashing problems by simply using the correct screenwash for the ambient temperatures.
Dont ask me what it is or the concentration as I buy it from the local supermarket. I use it undiluted and think it is marked as good to -25 on the 5 litre container.
I like the idea of a screenwasher jet that overshoots and hits the car behind. An excellent way to get rid of tailgaters who leave less than a two second gap behind the BX.

[mat_fenwick]

I've now drained and refilled with undiluted screenwash - can't remember what the minimum temp. was at the moment. This coincided wit the temperature rising by about 10 deg C so I can't comment yet on its effectiveness!

[mds141]

Matt try using cheap vodka from the local offy. Guarantee that won't freeze!

[Way2go]

Matt try using cheap vodka from the local offy. Guarantee that won't freeze!

Might trigger the "have you been drinking, Sir?" though, if stopped by the traffic plod.

[Vanny]

Good vodka freezes at minus 37c, cheap vodka freezes at just under 0c because it has so much water in! Then its full of sugar and leaves a lot of residue.

Screen wash can be a bit hit and miss too. We had some that was rated to -35c and was freezing up when it was -20c. We swapped to stuff that was only good to -25c and that was fine through to -30c, quality of screen wash is very hit and miss!


Perhaps we should do like the 205 boys and do a group order of heated windscreens? There is a company that will make them up to any spec. And the Ford patent has expired so we should see more and more of them in the UK.