Hi Sanford,

I hear ya. The human nose has incredible powers of detecting past odors.

Mine leaked at the same spot a few years ago. Nothing short of  cleaning with your favorite
soap and water will remove the residual 'smell'. There are a few "heater" cleaning sprays available
at your local FLAPS. Never used them myself.... yet. But, in general, turn on rear heater fan, spray
cleaning product into intake of rear heater fan..... hope it works? This does not remove the coolant
that no doubt flowed down onto the metal floor pan under the bench seat.

Other cleaning tips involve removing rear heater, rear storage box and cleaning the whole area.
All depends on how much time you want to invest to rid yourself of the odor.  Clamping the
rubber hoses that feed the rear heater is not that difficult.... then allowing full access to the area.

Good hunting.

Phil Z.  87 Camper without a rear-heater. Installed a forced air diesel furnace.... now that was allot
of work!