Must be a punctured hose. Take it to a shop for a diagnostic.
Answerremove the lower dash on the passenger side. This is not a fun job.
The coolant goes into the overflow bottle on the passenger side, fill it cold and do not over fill.
Oil. coolant, or grease on the floor. Things like a floor jack, or jack stands that you can trip over. Tools laying on the floor that can cause a slip.Slippery, cluttered floors.
If it sits over a cement floor, then no. If it is a nailed down floor, then you can, but you still have to install a cement board.
Sadly, when a passenger died they just threw the dead body over board.
If you see coolant Inside the vehicle on the passenger side, The Heater Core would be the problem.If the leak is out side and you see a puddle on the ground below the engine from the passenger side, It can be a Water pump, Heater hose, Over flow from the Reservoir tank, or an intake manifold gasket.If the leak is more underneath the vehicle on the passenger side, It might be a Heater Hose and/or Heater Pipe which supplies the rear heater with coolant (if the vehicle is equipped with rear heat) .
I would get advice from a professional. I suspect that the cement backed board (plaster board?) would crack and turn to powder under the flexing as people walk across the floor.
You couldn't tile directly over a plywood sub-floor because over time, the wood will be expanding. There are products you can use in between the plywood and tiles to keep them in place such as cement backer board.
Do you mean the base board? It is better if you can remove the base board then reattach on top of the new floor. It will give you the best look. If you butt the new wood up against the base boards you may have end cuts or little mistakes around the edges of the room that you will need to cover anyway. If you can not remove the base board you will probably have to add a strip of quarter round on top of the new floor and nailed to the original base board so that you have a finished look.
Thinset or Speet set would be better
The best way to repair particle board sub-flooring is to cut out the bad spot and replace with new board. You can only use vinyl and self stick tile over particle board. Ceramic tile cannot because the moisture in the thin-sets will break down the particle board.
You have a coolant leak.You have a coolant leak.