Infiniti Q45 1990-1996 4.5L V8 Engine Specifications

The 4.5L V8 engine, sometimes labeled as a 4.5L engine, was primarily used in the 1990-1996 Infiniti Q45. It is not directly compatible with other models without significant modifications. This engine features a VH45DE designation, with a 4.5L displacement, DOHC configuration, and 32 valves. It produces approximately 278-290 horsepower and 292 lb-ft of torque, depending on the model year. Compatibility with other vehicles would require custom mounts, wiring, and ECU adjustments.

The 4.5L V8 engine requires regular maintenance to ensure longevity. Key tasks include oil changes every 3,000-5,000 miles using 5W-30 synthetic oil, timing belt replacement every 60,000-90,000 miles, and spark plug replacement every 30,000 miles. Additionally, inspect and replace the water pump, serpentine belts, and coolant as needed. Regularly check for oil leaks, especially around the valve covers and oil pan, as these are common issues with this engine.

Replacing the timing belt on the 4.5L V8 engine involves several steps: 1) Disconnect the battery and remove the engine covers. 2) Remove the serpentine belt and accessory pulleys. 3) Drain the coolant and remove the radiator hoses. 4) Remove the crankshaft pulley and timing belt covers. 5) Align the timing marks on the crankshaft and camshafts. 6) Remove the old timing belt and install the new one, ensuring proper tension. 7) Reassemble components in reverse order. Use a service manual for detailed torque specifications and alignment procedures.

Common issues with the 4.5L V8 engine include rough idling, oil leaks, and overheating. For rough idling, check the spark plugs, ignition coils, and fuel injectors. Oil leaks often occur at the valve covers or oil pan gaskets; inspect and replace these seals as needed. Overheating may be caused by a failing water pump, thermostat, or radiator; check coolant levels and system components. Use an OBD-II scanner to diagnose any error codes and address underlying issues.

To optimize the 4.5L V8 engine's performance, consider upgrading the air intake and exhaust systems for better airflow. Use high-quality synthetic oil and ensure regular maintenance. A performance ECU tune can enhance horsepower and torque. Additionally, inspect and replace worn suspension components to improve handling. For track use, consider upgrading the cooling system and installing performance brake pads. Always ensure modifications comply with local regulations and do not compromise engine reliability.