Should you flush the Mercedes Benz radiator?

This article will explain the Mercedes Benz coolant system and answer the following questions: Should you flush the Mercedes Benz radiator? What are a radiator flush and cleaner? And when to flush the coolant radiator?

Should you flush the Mercedes Benz radiator?

No, You should not flush the Mercedes Benz radiator. The coolant system of the Mercedes Benz car is very complex and it needs proper training before working on the coolant system. The older models in the 1980s had very simple coolant systems and no special tools were required to perform simple tasks like radiator flush and replacing the coolant in the car.

The latest Mercedes Benz cars like the E class have multiple radiators and heat exchangers that use the primary coolant system. The coolant system consists of the following components:

  • Coolant expansion reservoir

The coolant expansion reservoir holds the coolant required for cooling the internal combustion engine. It is specifically designed to withstand high temperatures and pressure up to 1.7 bars. The coolant expansion reservoir also has a one-way valve in the coolant valve which helps to relieve excessive pressure in the coolant system.

There are two coolant reservoirs, one is for the primary circuit used to cool the engine and heat exchangers like engine & transmission oil coolers. The secondary coolant circuit is used for cooling the charger air system.

  • Radiator

Mercedes Benz radiators cool down the hot coolant extracted from the engine and send the cool coolant back again to the engine. The design is similar to conventional radiators but the size and the fin pattern can change according to the model.

A radiator cools down hot coolant by the air passing between the fins, Mercedes Benz radiators are designed to allow maximum surface area for the airflow over the fins while also minimising the dirt and dust accumulation.

  • Radiator Fan

A radiator fan is a large electric fan, installed directly behind the radiator. Since the vehicle can be in stationary condition when it is in city traffic, the electric fan cools down the radiator.

Mercedes Benz also uses radiator fan shutters to restrict the airflow over the radiator and bring the engine to operating temperature more quickly. The shutters are flaps operated by electric or vacuum actuators; they are in a closed position for only a few minutes during the warm-up phase. The flaps are spring-loaded, if there is any problem with the actuators, the spring force will keep the flaps in the open position.

  • Coolant  pump

The majority of coolant pumps in Mercedes Benz are electric. A coolant pump is a critical component of the coolant circuit and it pumps the coolant from the coolant reservoir to the internal combustion engine and back again to the coolant reservoir after it is cooled by the radiator. 

  • Auxiliary coolant pump 

Auxiliary coolant pumps are also electric and their main task is to support the main coolant pump and reduce the load on the cooling system.

  • Coolant thermostat

A coolant thermostat consists of a heating element that opens or closes the thermostat, depending on the operating mode. The heating element is controlled by the engine control unit according to the coolant temperature sensor in the cylinder head.

  • Coolant hoses

Coolant hoses connect different components of the coolant system, there is a complex network of coolant hoses in Mercedes Benz. The coolant hoses are mostly rubber pipes but Mercedes Benz also uses hard plastic and steel braided lines that allow the coolant to reach engine components like the turbocharger and charge air cooler.

When flushing the complete coolant system, a special tool is used that is available only at Mercedes Benz authorised dealerships. After draining the coolant from the drain screw in the radiator, the technician then connects the special tool to the coolant expansion reservoir. 

The tool is designed to create a vacuum in the entire coolant system and then when the intake valve on the tool is opened, fresh coolant which is filled in a large container is sucked into the coolant system. There is no air trapped in the system as all the air is sucked out by the tool.

Mercedes Benz has been using electric pumps in the coolant system since 2014, if there is air trapped in the coolant system and reaches the pump, it is not designed to work under that condition and the pump just shuts down. Unlike mechanical coolant pumps which can remove the air from the coolant circuit, electric pumps cannot do that. Hence, without the special tool, it is not possible to flush the radiator and replace the coolant.

What is a radiator flush and cleaner?

A radiator flush and cleaner is a liquid containing solvents like methyl pentane used to clean the entire coolant system. Wruth makes some good radiator flush and cleaner, only 250 ml is required one time to flush the radiator. 

It is added to the coolant expansion reservoir and the vehicle is kept running for a few minutes so that the radiator flush and cleaner is circulated through the entire system. It thoroughly cleans the entire cooling system and radiator by dissolving any deposits of grease or corrosion in the engine and radiator.

When to flush the coolant radiator?

The coolant radiator is flushed at the time of replacing the coolant in the system. It is also flushed if the coolant concentration is outside the specified range. Mercedes Benz coolant ideally contains 50 per cent water and 50 per cent antifreeze

The radiator is also flushed if there is engine oil mixed in the coolant circuit. This occurs due to a ruptured seal in the engine oil cooler. 

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The coolant systems in the Mercedes Benz cars have improved significantly, flushing the radiator every 30,000 Km or two years is no longer necessary as the efficiency of the coolant does not decrease over time. The Mercedes Benz antifreeze also has good resistance to corrosion so the coolant system stays clean compared to other brands.

FAQs: what is the use of Mercedes Benz radiator flush?

How do you flush a Mercedes Benz radiator?

All Mercedes Benz radiators have a drain screw at the bottom. To flush the radiator simply unscrew the drain plug halfway and open the coolant reservoir Cap, collect the escaping coolant in a suitable container. The coolant system is pressurised, hence never opening the coolant reservoir cap when coolant is at operating temperature.

How much does Mercedes Benz charge for a Coolant Flush?

Mercedes Benz can charge 100 to 120 USA for a coolant flush. Price of new coolant and labour is included. Depending on the model, the coolant capacity of the engine varies and most of the Mercedes Benz cars have two coolant reservoirs. Hence, the cost is high compared to other manufacturers.

How often should I flush my Mercedes Coolant?

Mercedes Benz coolant should be replaced after 8 to 10 years or more than 100,000 KM. If the coolant concentration is okay and there is no engine oil mixed in the coolant then there is no need to flush the cooling system.

Is flushing a radiator necessary?

No, flushing a radiator is not necessary, Mercedes Benz coolant can easily last for 10 years. Coolant concentration is checked using a refractometer, if the coolant concentration is out of specified range then coolant concentration is corrected and the radiator is flushed.