2018 Mercedes-Benz CLA45 AMG Is Overheating

Common Causes of Overheating in Your 2018 Mercedes-Benz CLA45 AMG and How to Resolve Them

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Reviewed by
Bo Fader
Written by RepairPal Car Genius
Updated January 14, 2025
0%
24% chance it's the
Thermostat
0%
41% chance it's the
Coolant leak (water pump, radiator, hose etc.)
0%
32% chance it's the
Radiator Fan
0%
3% chance it's
Something else
The most common reasons a 2018 Mercedes-Benz CLA45 AMG is overheating are a coolant leak (water pump, radiator, hose etc.), the radiator fan, or a failed thermostat.
  • Thermostat: A faulty thermostat can cause the engine to overheat or run too cool by failing to regulate the flow of coolant properly.
  • Coolant leak (water pump, radiator, hose etc.): A coolant leak can occur due to a damaged hose, a failing water pump, or a compromised radiator, leading to loss of coolant and potential engine overheating.
  • Radiator Fan: A faulty radiator fan can lead to engine overheating due to insufficient airflow over the radiator.
Proper diagnosis will determine the exact cause of your symptom, saving you money on unnecessary repairs. The diagnostic experts at RepairPal Certified shops have the right tools and experience to solve any symptom.

What are the initial diagnostic steps to take for an overheating 2018 Mercedes-Benz CLA45 AMG?

When addressing an overheating issue in your 2018 Mercedes-Benz CLA45 AMG, it's essential to start with a systematic diagnostic approach. Begin by checking the coolant level in the reservoir, as low levels can lead to overheating. If the coolant is adequate, inspect the cooling system for any visible leaks, particularly around hoses, the radiator, and the water pump, since leaks can significantly reduce coolant levels. Next, ensure that the radiator fan is operational; a malfunctioning fan can hinder the engine's cooling process. Following this, examine the thermostat to confirm it is opening and closing as it should, as a stuck thermostat can trap heat in the engine. Additionally, inspect the water pump for any signs of wear or damage, as it plays a crucial role in circulating coolant. Lastly, verify that the radiator cap is functioning correctly, as a faulty cap can disrupt the pressure in the cooling system, leading to overheating. By methodically following these steps, you can effectively diagnose and address the overheating issue in your vehicle.

What are the common problems that could cause a 2018 Mercedes-Benz CLA45 AMG to overheat?

When dealing with overheating in a 2018 Mercedes-Benz CLA45 AMG, it's crucial to understand the common problems that may be at play. One of the first things to check is the coolant level; low coolant can severely hinder the engine's ability to maintain optimal temperatures. If the coolant is at the right level, inspect the cooling system for any leaks, as even a small leak can lead to significant coolant loss and overheating. Another critical component to examine is the thermostat; if it’s stuck closed, it will prevent coolant from circulating, causing the engine to overheat. Additionally, the radiator should be inspected for clogs or leaks, which can obstruct the cooling process. The water pump is also vital, as a malfunctioning pump will fail to circulate coolant effectively. Lastly, ensure that the cooling fan is operational; if the fan motor or relay is faulty, it can lead to inadequate cooling. By systematically checking these components, DIYers can identify and address the overheating issues in their CLA45 AMG, ensuring the vehicle runs smoothly and efficiently.

How urgent is it to address the overheating issue in a 2018 Mercedes-Benz CLA45 AMG?

When it comes to the overheating issue in a 2018 Mercedes-Benz CLA45 AMG, urgency cannot be overstated. Overheating can lead to catastrophic engine damage, which not only incurs hefty repair costs but can also result in complete engine failure, leaving you with a non-operational vehicle. Additionally, persistent overheating negatively affects the car's performance and fuel efficiency, compromising your driving experience and reliability. Ignoring these symptoms poses significant safety risks, as an unexpected breakdown could endanger both the driver and passengers. Regular maintenance and immediate attention to overheating problems are essential for prolonging the vehicle's lifespan and ensuring it operates at peak performance. Therefore, if you notice any signs of overheating, it is crucial to address the issue without delay to prevent more severe consequences down the line.

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