Had the inevitable happen and limped home with wet floor and steam coming out of the vents. On inspection, the hoses down the firewall seem ok and the join is dry so I'm looking at the autoheat heater core (for~$200). I'm half way through the minimal removal procedure outlined somewhere here on AULRO but paused after talking to the heater core guy who says that ethylene glycol based coolants will corrode aluminium. He suggests NATRAD radiator conditioner plus water only. My impression was that the LR red coolant is ethylene glycol plus OAT so as a V8 owner you can see the dilemma. Any thoughts?
Also, with a blind loop plumbed into the heater pipes while I replace the core, the A/C works superbly! Has anyone thought of just putting a "summer tap" on these pipes permanently?

TIA Steve