Called my local guy, and I'm putting her in the shop for a flush & fill and a thermostat replacement (another $150 down the tubes). Anyway, I want to make sure the right stuff goes in. The old coolant that was in the car until it puked was dirty old brown/green coolant of unknown quality or brand (I jsut got the car a few months back). I want a happy/healthy CGT. So, what should be used in her?

I'll be replacing my coolant whenever I replace my radiator, which will be in a few weeks. I had a post not that far back asking what kind I should put in my 4K. If its anything like my car, just make sure its phosphate free! The stuff thats in my car is from the dealer, its bluish in color. We got a talking to about having coolant with phosphate from the Audi tech, perhaps this is why Im replacing my radiator!
Anyhow, just make sure its phosphate free.
HTH
Mike
85 4000S

Green coolant (ethylene glycol) is just fine for aluminum and your 4000. get some distilled water to mix with it and you don't need to worry about phosphate free or not. the hard water deposits in water bind with phosphates and create the mineral deposits in your system. if you use distilled water it has no particulate matter and there is no binding.

The anti-freeze raises/lowers boiling pt./freezing pt. plus has the nice additives.