Cold weather preparedness.

I can't really see how heating a small proportion of the screen wash tube via the engine helps. You still need additive to prevent freezing overnight and only a small section is actually heated, so you spray cold / hot / then cold again as you pump the tube out, so not even a hot wash (which can help).
​​I Had a VW with heated spray nozzles, I guess the plan was to help with it's frozen extremities on very cold nights as  nozzles can "air freeze" even with additives.
Could be wrong with my reasoning, just thinking about it as I actually like the solution/ heat exchanger used.
 

In my experience it is the nozzle that needs heating, not the liquid, as Mike says it can freeze even with additives.

Pity they don't make them for the Jimny, unless you can get them for another model that are the same size?

The nozzle freezes, because there the additives (usually alcohol) at the end of the nozzle evaporate and the remaining water freezes. So heated nozzles would be great.

Ford fit/fitted heater nozzles to some models. They were permanently wired through the ignition circuit. Last night was -7 deg. C and my nozzles were frozen. This is not the washer fluid but frost on the outside of the nozzle.
I wont to reiterate my previous comments. My experience goes back many years to my rallying days when we tried wrapping polythene tubing round a heater hose but found it only marginally effective. I have experimented with various systems including a 16ft double coil of copper brake pipe that ultimately proved OTT until I found that my present system proved effective and simple. The fact that it resembled the system used by Saab is purely coincidental but pleasing that they also consider that it is suitable for Swedish winter conditions.
So there you have it, I find the system works for me, know it's up to you.

Roger

Roger, that looks to be a really well-made assembly, nice work. If you decide to put them "in production," put me at the top of the list. (Seriously.)

I think if people did the maths on the fluid flow of a windscreen washer pump vs the output of an electric heating element, they would quickly understand why drawing the heat from the engine is a far superior solution to trying to heat the fluid electrically. (Heated nozzle tips being another matter, solving a different problem requiring less heat energy.)

Really impressed with the ingenuity, and particularly with the level of finish of the part in the photo. Thanks again for posting.

Thank you for your kind words Motacilla, but I will not be going into production. It's an interesting idea but age is taking it's toll and hours of toiling in my workshop does my back no good at all. Have you thought about that Saab one on Ebay? The price looks good, far lower than what I would need to charge.
I did toy with the idea of routing hot water through the washer bottle but my little inline device was far simpler and probably safer so that idea remained on the back burner.

Roger

Here's a vintage universal fit one on eBay, check the pipe stub sizes are suitable for the Jimny cooling system before you order.
Ebay

Hi Scimike.

That is the one I saw but didn't get a close up. Now that I have looked more closely I see that it fits into the top rad. hose which means that there will be some delay (a lot longer than mine) before hot water from the engine exits past the thermostat into the rad and you get warm water to the screen jets.
I don't personally like it so scrub my recommendation.

Roger

Roger

One thing I have noticed is that when the nozzles are blocked the passenger side clear first, this is probably explained as the T piece is closer to the passenger side and it is a shorter tube length. Also the exhaust is over that side.

So I have decided to re-route the washer pipe, go from the tank, wrap round the radiator coolant pipe ten times [just to warm it], then up the drivers side (so it is shorter to the drivers side), then the passenger side by reversing the T.

I have sourced nylon tube that has a much higher temperature range than PVC and will also wrap it in some [hot] water pipe insulation to stop it from getting too cold.

Together with the portable hot water bottle spray and deicer I should keep the screen clear.

Robin

Sounds like a good plan for simple pre heating.

The new to me 1984 gen 2 jimny got headlight washers. Original. All my former 1985-1988 SJ had them too, but no gen 3 jimny as far I know.