1985 GMC S15 Pickup Oil Type & Capacity

It depends on the engine: 2D Pickup Extra Cab, 2.2 S, MB1 uses 10W-30; 2D Pickup Extra Cab, 2.2 S, MC9 uses 10W-30; 2D Pickup Extra Cab, 2.5 E, 4WD, Automatic uses 10W-30; 2D Pickup Extra Cab, 2.5 E, 4WD, Standard, MC9 uses 10W-30; 2D Pickup Extra Cab, 2.5 E, 4WD, Standard, ML2 uses 10W-30; 2D Pickup Extra Cab, 2.5 E, RWD, Automatic uses 10W-30; 2D Pickup Extra Cab, 2.5 E, RWD, Standard, MC9 uses 10W-30; 2D Pickup Extra Cab, 2.5 E, RWD, Standard, ML3 uses 10W-30; 2D Pickup Extra Cab, 2.8 B, 4WD, Automatic uses 5W-30; 2D Pickup Extra Cab, 2.8 B, 4WD, Standard, MB1 uses 5W-30; 2D Pickup Extra Cab, 2.8 B, 4WD, Standard, MC9 uses 5W-30; 2D Pickup Extra Cab, 2.8 B, RWD, Automatic uses 5W-30; 2D Pickup Extra Cab, 2.8 B, RWD, Standard, MB1 uses 5W-30; 2D Pickup Extra Cab, 2.8 B, RWD, Standard, MC9 uses 5W-30; 2D Pickup, 1.9 A uses 5W-30; 2D Pickup, 2.2 S, MB1 uses 10W-30; 2D Pickup, 2.2 S, MC9 uses 10W-30; 2D Pickup, 2.5 E, 4WD, Automatic uses 10W-30; 2D Pickup, 2.5 E, 4WD, Standard, MC9 uses 10W-30; 2D Pickup, 2.5 E, 4WD, Standard, ML2 uses 10W-30; 2D Pickup, 2.5 E, RWD, Automatic uses 10W-30; 2D Pickup, 2.5 E, RWD, Standard, MC9 uses 10W-30; 2D Pickup, 2.5 E, RWD, Standard, ML3 uses 10W-30; 2D Pickup, 2.8 B, 4WD, Automatic uses 5W-30; 2D Pickup, 2.8 B, 4WD, Standard, MB1 uses 5W-30; 2D Pickup, 2.8 B, 4WD, Standard, MC9 uses 5W-30; 2D Pickup, 2.8 B, RWD, Automatic uses 5W-30; 2D Pickup, 2.8 B, RWD, Standard, MB1 uses 5W-30; 2D Pickup, 2.8 B, RWD, Standard, MC9 uses 5W-30.

Oil capacity depends on the engine: 2D Pickup Extra Cab, 2.2 S, MB1 holds 5.5 quarts with filter; 2D Pickup Extra Cab, 2.2 S, MC9 holds 5.5 quarts with filter; 2D Pickup Extra Cab, 2.5 E, 4WD, Automatic holds 3.0 quarts with filter; 2D Pickup Extra Cab, 2.5 E, 4WD, Standard, MC9 holds 3.0 quarts with filter; 2D Pickup Extra Cab, 2.5 E, 4WD, Standard, ML2 holds 3.0 quarts with filter; 2D Pickup Extra Cab, 2.5 E, RWD, Automatic holds 3.0 quarts with filter; 2D Pickup Extra Cab, 2.5 E, RWD, Standard, MC9 holds 3.0 quarts with filter; 2D Pickup Extra Cab, 2.5 E, RWD, Standard, ML3 holds 3.0 quarts with filter; 2D Pickup Extra Cab, 2.8 B, 4WD, Automatic holds 4.0 quarts with filter; 2D Pickup Extra Cab, 2.8 B, 4WD, Standard, MB1 holds 4.0 quarts with filter; 2D Pickup Extra Cab, 2.8 B, 4WD, Standard, MC9 holds 4.0 quarts with filter; 2D Pickup Extra Cab, 2.8 B, RWD, Automatic holds 4.0 quarts with filter; 2D Pickup Extra Cab, 2.8 B, RWD, Standard, MB1 holds 4.0 quarts with filter; 2D Pickup Extra Cab, 2.8 B, RWD, Standard, MC9 holds 4.0 quarts with filter; 2D Pickup, 1.9 A holds 4.0 quarts with filter; 2D Pickup, 2.2 S, MB1 holds 5.5 quarts with filter; 2D Pickup, 2.2 S, MC9 holds 5.5 quarts with filter; 2D Pickup, 2.5 E, 4WD, Automatic holds 3.0 quarts with filter; 2D Pickup, 2.5 E, 4WD, Standard, MC9 holds 3.0 quarts with filter; 2D Pickup, 2.5 E, 4WD, Standard, ML2 holds 3.0 quarts with filter; 2D Pickup, 2.5 E, RWD, Automatic holds 3.0 quarts with filter; 2D Pickup, 2.5 E, RWD, Standard, MC9 holds 3.0 quarts with filter; 2D Pickup, 2.5 E, RWD, Standard, ML3 holds 3.0 quarts with filter; 2D Pickup, 2.8 B, 4WD, Automatic holds 4.0 quarts with filter; 2D Pickup, 2.8 B, 4WD, Standard, MB1 holds 4.0 quarts with filter; 2D Pickup, 2.8 B, 4WD, Standard, MC9 holds 4.0 quarts with filter; 2D Pickup, 2.8 B, RWD, Automatic holds 4.0 quarts with filter; 2D Pickup, 2.8 B, RWD, Standard, MB1 holds 4.0 quarts with filter; 2D Pickup, 2.8 B, RWD, Standard, MC9 holds 4.0 quarts with filter.

Most 1985 GMC S15 Pickup owners follow a 5,000–7,500 mile interval with conventional oil, or up to 10,000 miles with full synthetic. Always check the oil life monitor if equipped, and consult your owner's manual — GMC recommends intervals based on driving conditions, not just mileage.

Yes. 10W-30 is widely available as a full synthetic, and synthetic is safe (often recommended) for the 1985 GMC S15 Pickup. What matters most is matching the factory viscosity and specification, then changing the oil and filter on schedule.