it will have the dreaded acc servo for the ACC system. This device is a black box shaped object mounted to the passenger side of the engine on the fender inside the engine compartment. Check it over for leakage of any kind. Run the ACC system by first running on defrost, fan should be on high and you get fuill heating. Then push the high auto button, with the temp wheel all the way in the red, ensure that the vent flaps change over and the heat continues to blow from the side vents and floor vents. Then turn the wheel all the way to the stop on the blu side, the fan should continue to clow but the temp should cool. Next push the low button, make sur ethe fan slows accordingly, finally push the compressor switch and see that the ac compressor starts running and the air turns cold.

The other things are:
easy starting when cold
while running undo the oil filler cap slowly and see if it has just a wisp of white smoke or if it sounds like a freight train is coming out of the valve cover.

These are some basic checks to ensure that certain systems are running. Otherwise you might pay an independant mechanic to chek it out but for that mch money you might be fine anyway.

I have my indy check out my cars, make a list of fixes, then I do them myself when I can...

Good luck and it sounds like it might be a great find.

__________________
'99 S420 - Mommies
'72 280SE 4.5 - looking to breathe life into it
'84 300SD Grey - Sold
'85 300SD Silver - Sold
'78 Ski Nautique