W210 E320 wagon heater core flush???
 

So I notice the other day the heat was just warm coming out the vents. So I figured I’d clean the duo valve and flush the heater core. On my quick inspection, I could not see were the hoses enter the fire wall. Plan to take a deeper look this weekend. Any advice would be appreciated!

look near the control box - there is a molded hose that clips into the false bulkhead and then into the valve, (right by the expansion tank)

On the passenger side the 2 hoses from the duo-valve connect to the heater core pipes underneath the water collector. It needs to be removed for access to the clamps - or remove the duo-valves and flush from the driver's side.

Recently had remarkable results with CRC Thermo Cure flush and it is supposed to be non-toxic.

Good luck!!!