If you don’t know what the message means, you may be concerned when you see the dreaded “Check coolant level” message on your Mercedes gauge cluster.
In this article, I will describe the meaning and causes of this alert, as well as how to resolve it. Let’s get started!
What Does a Coolant Do on a Mercedes?
Understanding coolant (also known as antifreeze) is helpful before diving into the warning light.
In the engine block and cylinder head, passages are drilled for water and ethylene glycol to circulate through to keep your engine running at optimal temperature.
Several vital functions are performed by coolant. As a first step, it absorbs heat generated during combustion and from hot parts of the engine.
In order to prevent components from overheating, it transfers this heat to the radiator.
Water-based mixtures can be cooled significantly below their freezing points by the use of coolants, as they are capable of lowering the freezing point substantially below that of normal water, which is 32 degrees Fahrenheit.
During frigid winter temperatures, this antifreeze effect prevents cracks and ruptures in the cooling system.
A coolant also allows liquids to operate without evaporating at temperatures well above 212°F, the boiling point of water.
To protect your Mercedes engine, you must maintain proper coolant levels and coolant health.
Mercedes “Check Coolant Level” Mean
It indicates to Mercedes owners that they may have a problem with their coolant system when the “check coolant level” message appears on the dashboard.
In more technical terms, it tells you that there may not be enough coolant in your system for it to function properly.
The coolant level sensor in the coolant reservoir is the main reason for this warning. A coolant sensor sends information to the car’s computer system about how much coolant is in the system.
Whenever the coolant level drops below a predetermined threshold, you are alerted by the computer.
Mercedes Benz “Check Coolant Level” Alert Causes
The “Check coolant level” warning can appear for several reasons, based on my experience as a mechanic. They include:
Normal usage causes low coolant levels
A low coolant level caused by excessive use is the most common cause of this message.
Evaporation and small leaks in a car’s cooling system can naturally result in a reduction in coolant levels. A sufficient level of coolant must be maintained through regular top-ups.
Coolant Leaks
Coolant leaks are a more serious problem. Mercedes’ coolant tanks, reservoir caps, radiators, and hoses are the most common areas to look for leaks.
This warning comes on when one of these components cracks or gets damaged.
Sensor isn’t working
In some cases, a faulty sensor may be associated with a normal coolant level.
The computer may trigger an erroneous warning if a malfunctioning sensor sends incorrect readings to it.
Sensor for windshield washers is faulty
One interesting fact is that coolant level warnings can sometimes be caused by faulty windshield washer sensors.
In most Mercedes models, the windshield washer sensor and the coolant level sensor are connected to the same circuit, resulting in an anomaly in this circuit. Thus, if one of the sensors malfunctions, the other may also be affected.
Check Coolant Level Message on Mercedes – Fix it and Reset it
Let’s look at how to resolve the warning now that I have explained the leading causes.
1. Top up the coolant (check it’s full)
My first recommendation is to check the antifreeze level in the coolant reservoir. You should top it up if it is low. Auto technicians recommend using G40-spec coolants or OEM Mercedes coolants.
Make sure the Mercedes is off and turned back on after adding more coolant. Once the level sensor has been reset, the message should automatically disappear.
2. Replace the sensor that detects coolant levels
You might have a malfunctioning coolant level sensor at the bottom of the water bottle (coolant tank) if you check the coolant expansion tank and find more than enough cold water (coolant).
A coolant level sensor replacement is necessary in this case.
As it comes with a new sensor and a new cap, I recommend replacing the entire coolant reservoir rather than just the sensor.
3. Replace the sensor that detects windscreen washer fluid
Mercedes may display a “check coolant level” message as a result of the windshield washer fluid level sensor.
It is recommended that you replace the coolant sensor if the coolant bottle has been changed and enough coolant has been added, but the warning still persists. It is likely that this will resolve the issue in most cases.
4. Test the coolant pressure
Your car should be taken to any Mercedes dealer or qualified independent garage if the three above steps don’t resolve the coolant warning message.
Upon arrival, the Technicians will give you a coolant pressure test in order to detect any leaks in the coolant, as well as to fix the leaks and to reset the dashboard warning for “check coolant level”.
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Frequently Asked Questions
What does the “Check Coolant Level” warning light mean?
The “Check Coolant Level” warning light indicates that the coolant level in your vehicle’s reservoir is low or that there may be a fault in the cooling system. This alert is crucial for preventing engine overheating and maintaining optimal performance.
What type of coolant should I use for my Mercedes?
Mercedes vehicles typically require a specific type of coolant, often a mixture of ethylene glycol and water. Always consult your owner’s manual or a dealership to ensure you are using the correct type and mixture ratio, usually 50/50.
When should I check my coolant level?
It’s advisable to check your coolant level regularly, especially before long trips or during extreme weather conditions. Additionally, if you see the “Check Coolant Level” warning light, you should inspect it immediately.
Can I drive my Mercedes with a low coolant level?
Driving with a low coolant level can lead to engine overheating, which may cause severe damage. If you receive this warning, it’s best to stop and address it immediately rather than continuing to drive.
How often should I top up my coolant?
The frequency of topping up your coolant depends on your driving conditions and vehicle usage. Regular checks are recommended, especially if you notice frequent drops in coolant levels, which could indicate a leak or other issues.
