Recommended Fluid
WARNING: This page is about a different car, the 1988 Isuzu Trooper II, 1988 Isuzu Pickup, 1988 Isuzu Impulse, and 1988 Isuzu I-Mark. However, it is still accessible from the selected car via links, so may be relevant.
At 0-90°F (-18 to 32°C) SAE 5W-30 engine oil.
At temperatures above 90°F (32°C) use SAE 40 engine oil.