160 degree water will definitely run a heater. Maybe your heater core is plugged.

I salute you for understanding that 160 is low for a non-race engine.

After you check what you have in there and check where it opens using the hot water/thermometer testing method, put a 180 or 185 thermostat in it and a 195 fan switch.

One of my cars had a problem with the thermostat sticking open. It was replaced by the dealer on a TSB.

R.