Unless you have either 1.) Service records documenting the change or 2.) The silver sticker that comes with the belt dated and affixed under the hood somewhere, you would need to assume that it has not been done.

Sorry, but there is no other way. The belt can look "perfect" right before it snaps. If the car's just been traded at 78k and there is no sticker and no records, I'd guess that it hasn't been changed, just because people rarely spend hundreds of bucks on routine maintainance right before they trade a car.

1998s are MOSTLY 70k belts. SOME (a few) late '98s have the later, 105k design, (but mine, built in 1997, doesn't)

"At some point the timing belt design was changed on 98s. From technical service bulletin 2210015 all with serial numbers 1266128- or higher have the newer design." http://www.brickboard.com/AWD/?id=581137

-d groundhog