In that case, they should repair the head gasket FOC, thoroughly flush all that red cr@p out and refill it with fresh, blue/green ethylene glycol, NOT that red Organic Acid Technology stuff that's really only suitable for use in cars made after 2000.
http://forums.aaca.org/topic/158713-...e-anti-freeze/
http://aagaskets.com.au/PDF/CoolantC...YourEngine.pdf
http://www.imcool.com/articles/antif...le-Excerpt.pdf
http://www.theminiforum.co.uk/forums...technology-ok/
https://en.wikipedia.org/wiki/Antifreeze
That's just a few results. In short it attacks the material used in older gaskets (including the head gasket) causing premature failure. If the engine had been stripped down and rebuilt using gaskets made with the newer materials and meticulously flushed, it wouldn't have been a problem.
However, i strongly suspect they didn't flush it meticulously leaving at least a small amount of the original ethylene glycol behind. When mixed with OAT antifreeze, a gel forms, blocking the waterways.
I've lost count now of the number of times i've seen HGF as a result of OAT coolant in older (pre-2000) engines. If your turbo was water-cooled as i believe a lot are on later 940s, because of the gel thing, there's a likelihood your turbo is now scrap as well.