If you're really concerned you could agree to have the appropriate leak detection dye added to engine oil, cooling, tranny, powersteering, and A/C system, and agree to a reputable/honest shop to detect these leaks.

You could even do a R134a or R12 sniffer in the vents.

Any leaks could be FIXED or you could negotiate a lower price.

:-) neil
1988 360TE AMG
1993 500E