GMC 1998 Savana Van Owner's Manual page 338

Short TripKity Maintenance Schedule
-=
Gasoline Engines
100,000 Miles (1 66 000 km) (Continued)
-
In hilly or mountainous terrain.
- When doing frequent trailer towing.
- Uses such as found in taxi, police or delivery service.
0
If you haven't used your vehicle under severe service conditions listed
previously and, therefore, haven't changed your automatic transmission fluid,
change both the fluid and filter.
An Emission Control Service.
0
Inspect Positive Crankcase Ventilation (PCV) valve.
150,000 Miles (240 000 km)
Drain, flush and refill cooling system (or every 60 months since last service,
Inspect hoses. Clean radiator, condenser, pressure cap and neck. Pressure test
cooling system and pressure cap.
whichever occurs first). See "Engine Coolant" in the Index for what to use.
MILEAGE
An Emission Control Service.
7-26