Howdy
dose anyone know if a mist spray of water in to the fan of the fan housing any benefit to cooling
Cheers
Yep. I've done it a few times before, takes an engine that's too hot and still getting hotter down to being just hot, knocks off enough so it's
like the temp outside is 5*C cooler as a rough guess.
I use a windscreen washer kit plumbed up to a fine garden mister nozzle pinched off something aimed into the fan intake, and a button on the dash.
Did the Perth temps over 40*C last week raise the temps a bit around town?
Hot up here last week too.........
Once had a 36 horse fan shroud & generator set up in the shed window, belt driven by a 240v motor, with a water feed, to cool the shed. That
worked OK, bit like spraying water into a fan. It’s the same theory as an evaporative air conditioner, only you usually get wet.
The theory :-
If you evaporate all the water into the air that it can take, on a very hot day, using an evaporative air conditioner, the very best you can hope for
is a 15 degree temperature drop (and almost 100% humidity). That would be good for your motor.
If you get free water on the fins, the “Latent Heat of Vaporisation” rules come into play. You are now creating steam and that will remove a lot
of heat energy from the metal, but only from that contact area. The fins will carry some heat around to that location but the steam will do nothing
as it passes over the rest of the fin area.
VWs (and all air cooled engines) are notorious for having large temperature variations from one part of a head or barrel to the other. The
manufacturers work hard to limit this but it’s never perfect. Probably shouldn't make it worse.
(My) Conclusion :-
It will work great with a very limited amount of water, enough to completely evaporate before too much hits the metal. If you put too much in you may
cause “cold spots”, e.g. more problems that you solve.
Might be better off spraying the water straight onto your external, or perhaps dog house, oil cooler (not a pre-dog house type obviously). That
won’t harm anything, takes away lots of engine heat, and makes the oil work much better too. All good things.
That’s what I think
Cheers
Tony
Thanks Guys
My thinking is when getting on the boost , like water injection to the intake , this may help to keep things a little safer for the motor.
I'll have to do a bit more surfing
Cheers 
Try this
http://www.coolingmist.com/coolingmist/instructions/PROTANK1.pdf
We Use windscreen washer fluid in the bottle