So, after renting a pressure kit, the diagnosis was trivial. At about 10 PSI, I found the gasket under the thermostat cover (aftermarket unit) was seeping all around. I torqued those down and it stopped. Then I pumped it up to about 15 and started getting blow-through past the return hose clamp right on the top (thermostat end). Again, trivial fix. After it held 15 PSI for about 10 minutes, I backed it out of the garage, sprayed down all that nastiness with simple-green and a lot of water, and drove around for a while. I'll let it cool and test again tomorrow, but I think I fixed it. Now for my wife's Audi...at least her coolant is a different color

Dan
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2005 Silver CRD Limited

245/75R16 GoodYear Duratracs
Fumoto drain | ProVent CCV Filter
Stanadyne FM100 filter | Cummins fuel pump
GDE Eco | SEGR | BoulderBars | FrankenLift | Frankenskids