Having suffered the ubiquitous failure of the blend door flaps in the aircon of my 2000 WJ (4.7L V8) – I effected a winter fix by locking the flap position at full heat. Now that summer is approaching in the northern hemisphere – full heat is no longer required, and I now cannot make use of the cooling offered by the aircon system.

I could hack into the aircon duct work again and let the flaps fall to full cool, but I have identified two possible (simpler) fixes and wanted your thoughts on the merits of each and possible problems therein.

Option one is to clamp either of the hose lines to the heater matrix – thereby blocking the flow of hot water to the heater matrix.
The second option is to disconnect both hoses from the heater matrix and use a union to connect the two hose ends to one another – providing a flow path for the water that would otherwise have flown through the heater matrix.

Option one is easier to effect, but possible problems include permanent crush/deformation of the hose, such that releasing the clamp will not allow water flow through the hose. I also have a concern that by blocking the heater matrix flow, I could cause other problems in engine cooling.

I would welcome your thoughts on my proposed fixes, and potential problems.

 

Use the union. While the engine is cold, the "bypass" is through the heater core, normally.

Ron

 

I wouldn't clamp the hose, just seems like a bad idea to block something that may have force behind it.