The 1998 Chevrolet Blazer was manufactured with the 4.3 L V-6 engine that has an integrated oil pan on the low side of the motor. Removing this pan is challenging, as many of the front end components must be removed first, or at least moved out of the way. There is no need to remove the entire engine-- the pan can be taken out by an average backyard mechanic in about six hours.
Jack the truck up and place it on the jack stands, then remove the front wheels for better access to the underside.
Drain the oil from the oil pan by turning the drain plug in a counterclockwise direction, then allowing the oil to fall into the drain pan.
Remove the skid plate by turning the hex-head bolts in a counterclockwise direction. The plate will fall off once these bolts are freed.
Disconnect the front axles from the hub and differential by turning their bolts in a counterclockwise direction. The constant velocity joints and axle are a single unit, and once the bolts holding it to the hub and differential are removed, it will come out in one piece.
Disconnect the pitman arm and idler arm, and move them to the side for better access at the oil pan.
Unbolt the differential from its mounts by turning the bolts in a counterclockwise direction. The differential is extremely heavy, and must be supported by a jack during this process. It is connected to the frame and the transfer case, but once the frame mounts are loosened the differential can be lowered to gain access to the oil pan.
Unbolt the oil pan from the truck by turning all of its bolts in a counterclockwise direction. There should be 16 bolts to be in the lip around the pan. All must be removed, and there are two in the very back that may be hidden by rubber caps. This area of the motor is notoriously dirty, and some bolts may be greasy or hard to locate. With these bolts free, the pan will drop down and can be manipulated out of the truck towards the transmission and transfer case.
