I ran across an ad from R&M Specialty Products in Toyota Trails magazine for their hot water
shower kit. This gadget was too cool (should I say hot) to pass up. I
thought about doing my own design for one, but time constraints led to
ordering one already built. I ordered the basic kit which includes the
My original plan was to install the heat exchanger under the truck,
near the rear heater, tapping into the heater lines there. After
getting the unit in hand and looking for a suitable mounting location,
I decided this was not an ideal location.
found that the driver's side fender was a better location for access. I
pulled out the wheel well liner and fender and verified there was
enough room to mount the exchanger. The heat exchanger comes with two
1/2" hose-barb connections angled out at 45°. To penetrate
through the fender wall far enough, I soldered a 45° 1/2"
copper angle, a 1" long copper nipple and a 1/2" brass hose
barb each of the existing coolant hose connections on the exchanger. I
cut two holes in the fender and mounted the exchanger to the fender
wall with the supplied bracket using an existing threaded hole. I
replaced the single hose between the heater valve to the rear heater
pipe with two lengths of 1/2" heater hose, one from the valve to
the exchanger and one fromt he excahnger to the rear heater pipe. When
the rear heater valve is opened, hot coolant flows through the
exchanger to heat the shower water. Water temperature can be regulated
by adjusting the rear heater valve as well as the flow through the
(view of driver's side wheel well - looking up and forward). I used
some lengths of 1/2" garden hose to attach to the exchanger and
run out of the wheel well to ...
... the winch tray on my front bumper. Quick connect fittings on the
hose ends allow quick shower setup. There is enough extra hose (~20')
in the basic kit to allow direct pumping from a stream or lake, or a
3-5 gallon bucket will provide enough water for a decent shower in case
the water source is too far away to reach with the hose. I actually
recommend this technique as you keep soap out of the water source.
The shower is set up as follows:
I had initially plumbed the heat exchanger in-line with the rear heater
in my 4Runner, making use of the heater control valve in the center
console to adjust shower temperature. I found this a little
inconvenient running back and forth, dripping water inside the truck,
etc. Plus I wanted to remove the rear heater, since it was prone to
leaks and was taking up precious room in the truck. So I put the heat
exchanger in place of the rear heater loop. Not wanting it to have
coolant flowing all the time, I added a water valve to allow it to be
shut off and it made a handy temperature control:
The coolant valve handle is visible in the lower left corner of the
above picture. Its in-line with the copper pipe running through the
inner fender wall that is in turn soldered to the copper heat
exchanger. It is so much easier to adjust the temperature now, since I
normally hook the shower head to the up-raised hood and set the shower
pump unit on the front bumper.
So, how does it work?
- Marvelous, simply marvelous!
I find it best to take a shower right after you pull into camp after a
hard, dusty day of wheeling. The engine is hot and the dirt is fresh.
It only takes a minute or two to set up. Leave the engine idling to
circulate coolant and you can shower until you either pump the lake dry
or run out of gas! Alternately, a collapsible bucket will hold enough
water for a quick rinse or even shove the pickup hose into a 5 gallon
water jug and go to it. If the engine is hot and the t-stat is open, it
will take a few minutes to get the 'stat to close a bit to allow full
flow to the heater. If using a bucket, just let the water circulate
through the system back into the bucket for a few minutes while you get
ready. I find a pair of sandals is ideal to wear to keep your feet out
of the mud and I carry a pair of swim trunks, a bottle of biodegradable
soap and a towel in my "shower kit".
1 R&M Hot Water Shower kit $259+tax&shipping (1997 pricing)
- Misc plumbing supplies varies
- Some copper pipe sweating may be involved as well a sheet metal cutting.
R&M Specialty Products
P.O. Box 1683, Dept. RCB
Windsor, CA. 95492
There are several options availible in case you want to "roll your
[Last updated: 30.September.2019]