Recommended Fluid
WARNING: This page is about a different car, the 1989 Isuzu Trooper II, 1989 Isuzu Trooper, 1989 Isuzu Pickup, 1989 Isuzu Impulse, and 1989 Isuzu Amigo. However, it is still accessible from the selected car via links, so may be relevant.
For temperatures of 0-90°F (-18 to 32°C), use SAE 5W-30 engine oil. Above 90°F (32°C), use SAE 40 engine oil.