I have a Yanmar 3HM with an Sendor aftermarket heat exchanger. I'd like to drain the fresh water coolant from the engine but the engine is mounted in reverse. This means that the fresh water pump is accessible only by crawling through a cockpit locker on my belly(bad) but the heat exchanger is accessible by removing the companionway steps (good). Normally I would drain the engine (fresh water not raw/salt water) coolant by removing the output hose on the fresh water pump but that is difficult soooo I thought I could accomplish the same thing by removing the coolant hose supplying fresh water to the heat exchanger.

Will this work? Does it matter which hose I remove the heat exchanger (and pipe to a bucket)? Any suggestions? Thanks