Building a mist system for your radiator is pretty easy. We built one for our bus when we brought it out from NC. Had to have the radiator rebuilt by
East Texas Radiator in Longview. Great folks. But the 100F+ temps were still causing the bus to overheat on the interstate. Luckily we were moving and we had almost all the parts to build a misting system in the bus. We sat in the parking lot at the Lowes in Odessa/Midland (not sure which or if there is only one). The ladies in the garden dept were kind enough to let us fill our tanks with their potable water.
We used...
>a drip irrigation system for a garden (I had two sets still in the boxes. I had bought them two years earlier at a Home Depot where they were on clearance sale for fall.. SEE! I had a use for them!)
>12vDC Shurflo 2088 water pump (too much pressure... kept blowing the misters little heads off) That pump is now being used inside the Class C... or the Food Cart... I had two extra pumps and don't remember which is which
> 30 gallon fresh water tank (this is now the fresh tank for the bus)
>electrical zip ties to attach the tubing to the grill of the bus (gotta love those zip ties!) and a couple of hose clamps
From Lowes, we bought a 12vDC toggle switch (to turn the pump on as needed) and some more mister heads since we kept blowing them apart. Did well to keep the temps down. Getting off the interstate helped too. We took primary roads from Odessa/Midland into NM (found a
NICE bus friendly public park in Hobbs thanks to
Don Wright's Free & Cheap Campgrounds - Western Edition directory and wallydocked at Sam's Club in Roswell (members but Wal-Mart next door allows parking as well) where they have diesel at their pumps and you CAN get a 40 ft bus towing a Jeep Grand Cherokee into the only diesel pump!)then on to Socorro. Crossed the
Valley of Fire with no problems (did not stop to check out the
campground. Whenever the temp gauge on the bus started to climb, David hit the toggle switch and it cooled right down.
The temporary mister system that we built has since been dismantled. I have a different plan for our misting system...
Instead of using misters, I'm using a (
1/4" punched soaker tubing) that has tiny pin holes in it. You could use a non punched tubing and simply poke holes in it where needed with a crafter's "t" pin or quilters pin. They are thicker pins and would make a little bigger hole but not too big. that way you only need to buy one type of hose and won't need to splice in any different hoses. You can also attach the hose and THEN poke your little holes in it. But my hose is already punched and I have almost 50 ft of it leftover from the drip kit.

I will secure the tubing onto the back side of the grill over the radiator with elastometic adhesive/roof patch (It's clear but not silicone). I will have a drain on the end of the tubing so that I can drain the water out in the winter. The supply water will come from our fresh tank (that has been filled with softened, filtered water). We have a tiny very low flow
1gpm 12vDC water pump that will supply the water (this is the one we have). It will have a toggle switch next to the driver on the switch panel to turn the little pump on/off as needed. I will have a shut off valve on the line to the pump so that it can be shut down. The mister pump (and our "house" water pump) will set inside the same insulated box the fresh tank is in because it will be heated in the winter time.
WHY "softened, filtered" water? Because we filter all our water straight from the hose (sediment plus a .5 micron filter to filter out the nasty "bugs") before it ever sees the interior of our RV... that includes fresh holding tanks. I want a softener because the water we have run into is full of minerals. The lime scale we have built up since moving out west is terrible. I even flushed our Class C's 6 gallon water heater with a couple gallons of white vinegar... and then had to remove all the faucet screens to get the limescale debris out of the water lines (I ran the water so that the vinegar was in the water lines then let it set for several hours... a long hot vinegar scented shower was all it took to flush the water heater... plus stripped shampoo/conditioner film out of my hair). The minerals in the water here is so bad, I am concerned that it will clog up the misters. The tubing stuff only requires a straight needle to unclog or to make a bigger hole if needed.
This is NOT my idea. I originally ran across this over on
Ian's Bus (Coach) BBS. Eagle Buses (what we had), and some other coaches, have their radiators on the sides of the bus.They have a nasty tendency to overheat when climbing (slowly) up a hill or while sitting in traffic. This is what those guys were doing and it is a tried and true system. I figure if it is good enough for a bus shell that costs $30K and up, then it was good enough for my $1400 skoolie shell.