Located on the passenger side of the dashboard. Open the passenger door and pull the small cover on the side of the dash.
You can access the full, original factory owner's manual through several reliable digital sources:
Located in the engine compartment on the passenger side, near the battery. Chevrolet Venture 2003 Manual
Inspect engine air filter and replace if dirty.
7.4 quarts (7.0L) for a drain and refill. Use DEXRON-III Automatic Transmission Fluid. Fuel Tank: 25 gallons (approx. 95 liters). 3. Essential Maintenance Schedule Located on the passenger side of the dashboard
4.5 quarts (4.3L) with filter. Recommended: SAE 5W-30 .
The 2003 Venture has a few known quirks often mentioned in technical guides: Chevrolet Venture 2003 Manual
11.3 quarts (10.7L) for standard cooling; 13.6 quarts (12.9L) with rear heating. Use DEX-COOL (orange).