1997 Chevrolet Blazer Owner's Manual - Page 267

Engine Oil Additives Don't add anything to your oil. Your GM dealer is ready to advise if you think something should be added. When to Change Engine Oil If any one of these is true for you. use the short tripkity . maintenance schedule: Driving under these conditions causes engine oil to break down sooner. If any one of these is true for your vehicle, then you need to change your oil and filter every 3.000 miles ( 5 000 km) or 3 months -- whichever occllrs first. If none of them is true, use the long trip/highway maintenance schedule. Change the oil and filter every 7,500 miles ( 12 500 km) or 12 months -- whichever occurs first. Drivinga vehicle with a fully warmed engine under highway conditions causes engine oil to break down slower. a Most trips are less than 5 to 10 miles ( 8 to 16 km). This is particularly important when outside temperatures are below freezing. a Most trips include extensive idling (such as frequent driving in stop-and-go traffic). a You operate your vehicle in dusty areas or off-road frequently. 0 Remote Oil Filter (Four-wheel Drive) The access door for the remote oil filter is in the steering linkage shield assembly located under the radiator support. Twist the screw to unlock or lock the door. Make sure if you open the door. it is securely closed I when ~ O L are finished. You frequently tow a trailer or use a currier on top of your vehicle. a The vehicle is used for delivery service. police, taxi or other commercial application. 6-12