After owning two bays, it’s quite novel to have the good Vanagon heat. The rear heaters are prone to leaks after 20 years, however, which can create a nasty mess. Around my rear heater, the floor padding was moist and icky, and you could see the steam pouring up if you turned it on.
(washer fluid has nothing to do with the heater)
I found a reliably rebuilt rear heater pretty cheaply. When I’ve done the swap, I’ll assess my current one and maybe rebuild it and throw it up on ebay. I’ll also need to add some ductwork to use the heater under my “new” ’68 Westy Z-bed.