1991 BMW 735i

Introduction:

The 1991 BMW 735i is a luxurious sedan powered by a 3.5-liter inline-6 engine that generates 215 horsepower and 225 lb-ft of torque. It comes equipped with a 4-speed automatic transmission. The 735i is known for its refined driving experience, spacious interior, and advanced features. However, it has also been plagued by several issues throughout its production run.

Engine

3.5L M30B35 Inline-6 Engine

• Head Gasket Failure: Premature failure of the head gasket can lead to coolant and oil leaks, overheating, and engine damage. Repairs involve replacing the head gasket, cylinder head bolts, and associated gaskets. Estimated cost to fix: $1,500 - $2,500+
• Intake Manifold Gasket Leak: The intake manifold gasket can develop leaks, causing vacuum loss and rough idling. Replacing the gasket is the solution. Estimated cost to fix: $500 - $1,000
• Camshaft Position Sensor Failure: A faulty camshaft position sensor can cause engine stalling, poor performance, and difficulty starting. Replacing the sensor resolves the issue. Estimated cost to fix: $200 - $300
• Fuel Injector Failure: Failed fuel injectors can result in misfires, reduced power, and increased fuel consumption. Replacing the faulty injectors is necessary. Estimated cost to fix: $50 - $500 per injector
• Recalls: None Found

Transmission

• 4-Speed ZF 4HP22 Automatic Transmission

• Harsh Shifting: Erratic or sudden gear changes can occur due to worn solenoids, valve body issues, or transmission fluid problems. Overhauling the transmission is usually required. Estimated cost to fix: $2,000 - $3,500+
• No Reverse Gear: Failure of the reverse gear can be caused by worn clutch plates or broken gear sets. Transmission removal and repair are necessary. Estimated cost to fix: $1,500 - $2,500+
• Recalls: None Found

Suspension

• Strut Mount Failure: Worn strut mounts can lead to excessive noise, vibration, and decreased handling. Replacing the strut mounts is the fix. Estimated cost to fix: $300 - $500 per side
• Control Arm Bushing Wear: Worn control arm bushings can cause loose steering, poor handling, and premature tire wear. Replacing the bushings is the solution. Estimated cost to fix: $400 - $800 per side

Electrical

• Window Regulator Failure: Faulty window regulators can cause the windows to become inoperable. Replacing the regulator motor or gear is necessary. Estimated cost to fix: $200 - $500 per window
• Alternator Failure: A malfunctioning alternator can lead to charging system problems, battery drain, and electrical component failures. Replacing the alternator is the solution. Estimated cost to fix: $500 - $800
• O2 Sensor Failure: Oxygen sensors monitor exhaust gas and adjust fuel mixture. When they fail, engine performance and fuel economy can suffer. Replacing the O2 sensors is the fix. Estimated cost to fix: $100 - $250 per sensor
• Recalls: None Found

Exterior

• Sunroof Drain Clogs: Accumulation of debris in the sunroof drains can lead to water leaks into the cabin. Cleaning or unclogging the drains is the fix. Estimated cost to fix: Less than $100

Interior

• Climate Control Unit Failure: The climate control unit can malfunction, leading to incorrect temperature settings or fan operation. Replacing the unit is necessary. Estimated cost to fix: $400 - $800

Summary:

The 1991 BMW 735i has various issues that can be costly to repair. Engine problems like head gasket failure and fuel injector failure can be severe and expensive to fix. Transmission issues such as harsh shifting and no reverse gear can also be significant and require professional attention. While the electrical and interior issues are generally less severe, they can still be inconvenient and require repairs. Overall, potential buyers should be aware of these issues and factor in the potential costs of maintenance and repairs when considering purchasing this vehicle.