2021 Mercedes-Benz OH 1621

The 2021 Mercedes-Benz OH 1621 is a bus chassis, primarily used in South America and other markets outside of North America. It’s known for its robust build and adaptability to various bus body configurations. The engine option available is the OM 924 LA, a 4.8L four-cylinder diesel engine producing around 208 horsepower and 590 lb-ft of torque. While praised for its reliability and fuel efficiency in demanding urban environments, some owners have reported issues with specific components. Because this is a chassis and not a complete vehicle, many issues can stem from the body installed on the chassis by third-party manufacturers.

Engine

OM 924 LA (4.8L Diesel)

• Turbocharger Failure
  • Description/Symptoms: Reduced engine power, excessive black smoke from the exhaust, whistling or whining noise from the turbocharger.
  • Solution: Replace the turbocharger assembly. Check and clean or replace air filters and inspect the oil supply line to the turbocharger to prevent recurrence.
  • Estimated Cost to Fix: $1,500 - $3,000+
  • Recalls: None Found
• Fuel Injector Issues
  • Description/Symptoms: Rough idling, misfires, decreased fuel economy, black smoke, and potential engine knocking.
  • Solution: Diagnose the specific injector(s) causing the problem. Replace faulty injectors. Ensure proper calibration of the fuel injection system.
  • Estimated Cost to Fix: $400 - $1,200+ (depending on the number of injectors)
  • Recalls: None Found

Transmission

No Issues Found

Suspension

• Air Suspension Compressor Failure (if equipped)
  • Description/Symptoms: The bus sags on one or more sides, ride height is uneven, the compressor runs constantly or not at all, error messages on the dashboard.
  • Solution: Replace the air suspension compressor. Inspect and repair any leaks in the air lines or air bags.
  • Estimated Cost to Fix: $800 - $2,000+
  • Recalls: None Found
• Air Bag Leaks (if equipped)
  • Description/Symptoms: Hissing sound from the air springs, sagging of the bus, reduced ride comfort, the compressor working overtime.
  • Solution: Replace the leaking air bag(s). Inspect the airlines and fittings for damage or leaks.
  • Estimated Cost to Fix: $300 - $800+ per air bag
  • Recalls: None Found

Electrical

• Sensor Malfunctions
  • Description/Symptoms: Engine warning lights, transmission issues, erratic gauge readings, and overall inconsistent operation. Common sensors that fail include ABS sensors, speed sensors, and coolant temperature sensors.
  • Solution: Diagnose and replace the malfunctioning sensor. Check wiring and connectors for corrosion or damage.
  • Estimated Cost to Fix: $100 - $500+ per sensor
  • Recalls: None Found
• Wiring Harness Issues
  • Description/Symptoms: Intermittent electrical problems, difficulty starting, lights flickering, and potential short circuits. Common areas are around the engine and areas with excessive vibration.
  • Solution: Inspect the wiring harness for damage, chafing, or corrosion. Repair or replace damaged sections of the harness. Ensure proper grounding.
  • Estimated Cost to Fix: $200 - $1,000+
  • Recalls: None Found

Exterior

No Issues Found (excluding normal wear and tear items like paint)

Interior

No Issues Found (excluding normal wear and tear items such as upholstery)

Summary

The 2021 Mercedes-Benz OH 1621 chassis generally exhibits reasonable reliability, particularly for its intended heavy-duty applications. The most commonly reported issues revolve around the engine’s turbocharger and fuel injectors, as well as electrical components like sensors and wiring harnesses. Suspension issues related to air systems are also noted when equipped. Repair costs can vary significantly, from a few hundred dollars for sensor replacements to several thousand dollars for major engine or suspension overhauls. The severity of these issues can range from inconvenient operational problems to significant downtime, so proper maintenance and early detection are crucial.