[Barry Rooker]

First off, any oil that's been in the engine is coal black. Then there's hydraulic fluid for the engine fan & the steering, it's red. There's also the HWH slideout fluid, a typical oil look. Transmission fluid is also red. The hydraulic fluid resevoir is just under your closet floor. The engine's crankcase breather is just under the floor. Some engine coolant is above your floor in the radiator's expansion tank, the tank with the pressure cap. Red coolant usually. And on general principles, I like you having a perfectly dry floor under your coach. Tell us more about that oil stain please.