My 93 FD has a problem in a white powder buildup (maybe Aluminum oxide) that clogs the valve that leads to the heater core so that my heater is not strong at all. Something must be corroding and causing this problem. Could it be the heater core itself or...? Over the course of a year this problem has resurfaced after haveing completly cleaned out the intake manifold. How do I solve this? more ground wires? Sacraficial anode?

Thanks,
Corbet

 

If you use a voltmeter, you can check for electrolosis. Put one end to ground and the other into the coolant. Does it show voltage? If it does, try adding some Redline water wetter, it has a lot of sacrificial anodes. That should take care of it. I'm assuming you have not used any block sealer, nor installed a new radiator. Almost all manufacturers use some type of "sealer" in the rads to prevent leaks. Also you know you don't have a bad water seal letting combustion gas into the cooling system? Rob

 

According to my mechanic, this has been a problem with RX7's since the 70's. I've decided to try the NPG from Evans cooling, as they are using Propylene GLycol in new European cars these days. In theory there is no corrosion because electrolosis can't occur in this solution that contains no water.