I think that Champa is offering some very good advice. Decent 300E's can be had from the South with no rust. I've seen them between about $5,500 and $9,000 for late eighties examples in great condition.
$2,750 for a car with a known bad motor and who knows what else wrong, may be a ticket to nowhere. See Chuck Taylors post regarding his air conditioner horrors. You could end up with another $2K or more in the air conditioner.
I really believe that at this price in this condition is not a good deal. This is a parts car at best. It should be bought for a parts car price.
My $0.02, Good luck,
'84 Euro 240D, 523K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in