The nozzle costs about $6. One of your misting nozzles might work.
Then you need a 12v pump that will push the water at about 50psi.
The hose I used is cheap polly, a few cents a foot.
I used the windshield washer tank. I stopped every 20 minutes to refill.
The wiring was all temp. with a cig. lighter plug on then end. I ran the wires out the hood and in the door.

RV water pumps are 12v and have enough pressure. If you can scrounge this part, the rest of it is almost free.

This is not for a permanent install, just one day temporary. After running 4 to 8 gallons through it, it is either getting better or it's not.

__________________
Greg
2012 S350 BlueTEC 4Matic
2007 ML 320 CDI
2007 Leisure Travel Serenity
2006 Sprinter 432k
2005 E320 CDI
1998 SLK230 (teal)
1998 SLK230 (silver)
1996 E300D 99k, 30k on WVO
Previous:
1983 240D, on WVO
1982 300D, on WVO
1983 300CD, on WVO
1986 300SDL 237k, 25k on WVO (Deerslayer)
1991 350SDL 249k, 56k on WVO - Retired to a car spa in Phoenix
1983 380 SEC w/603 diesel, 8k on WVO
1996 E300D 351k, 177k on WVO