I have an aluminum radiator (with plastic sides) that I salvaged off an 89 740 with 45,000 miles on it. It's been stored for 8 years now - and the big mistake I made was not covering any of the radiator/tranny ports during it's storage. The radiator itself is in excellent condition, and the plastic seems brand-new. I've especially checked for brittle ports etc and there are none.

I just cleaned / flushed both the tranny-cooler and the radiator sections. After cleaning the radiator I noticed the presence of white powdery-sediment when draining it. On closer inspection through the large radiator ports, I find this powder gathered around the edges of the flat-tubes that are visible through the port. The powder rubs off easily onto my finger when I run it along the ends of the tubes.

So - is this powder aluminum-oxide that has formed due to the bad storage of this radiator (I should definitely have covered the ports - though maybe it would have formed anyway) ? And if so can it be flushed or could the problem be pervasive enough to cause a leak in the near future ? I've done a quick presure-test on it - and it seems fine. I'm just concerned by that powder... My current radiator is copper/brass, and it's developed a leak where the upper-hose port meets the radiator - so I was planning to swap them out until I get the copper one fixed.

If a flush would work - any brands that work well ?

Also: Can the copper-crack be fixed using a high-wattage soldering iron, or should a torch be used ? Any info on the tools required for the job would be great - especially the type of solder to be used. I have a lot of experience using soldering-irons, but it's all been on circuit-boards, not on plumbing - so now would be a great time to start !

Thanks,

Noel
1985 740 GLE