How Often Should the Coolant in a Mercedes-Benz E-Class Be Replaced?
2 Answers
The coolant in a Mercedes-Benz E-Class generally needs to be replaced every 2 years or 40,000 kilometers. This is just a reference interval. For commercial vehicles with higher mileage, the replacement interval should be shorter. Since driving conditions vary for each vehicle, the replacement should be based on actual usage. Check the coolant level regularly and top it up if it is low. If suspended particles, sediment, or discoloration are observed in the coolant, replace it immediately and clean the system. Coolant Replacement Method: Before a complete coolant replacement, conduct a thorough inspection to check for leaks or cracks in all pipes, with a focus on the five-way hose. The five-way hose, named for its five connecting interfaces, distributes coolant to different parts of the car. If any leakage is detected in this section, replace the hose or reseal the connections as needed. Drain the old coolant and flush the system with clean water. Add water to the coolant reservoir and continuously flush the engine cooling system. Then, start the engine and let it idle for 3 to 5 minutes to circulate the water. Initially, the drained water may appear slightly pinkish. Continue flushing until the water runs clear. Remember to disconnect the heater hose and drain the water from the heater core. After draining for about an hour, add new coolant through the radiator hose to allow quick flow into the radiator. Then, fill the coolant reservoir with another bottle of coolant until it is nearly full. Run the engine for about 10 minutes. As air is purged from the cooling system, the coolant level will drop. Top up the coolant to the "MAXT" mark on the reservoir.
I've been driving a Mercedes-Benz E-Class for several years and always pay attention to maintenance. I remember when I first bought it, the salesperson reminded me that the coolant was long-life and usually didn't need frequent replacement. According to the official Mercedes-Benz user manual, the recommended interval for changing the coolant in an E-Class is every 5 years or around 100,000 kilometers, which is much longer than most other cars. This is because it uses organic acid technology, which offers strong anti-corrosion properties and protects the engine from overheating or rusting. However, I make it a habit to check the coolant level and color every year before winter—if it becomes cloudy or drops below the minimum line, I take it in for service immediately. Coolant is like the heart's lubricant for the car; if it deteriorates, it can lead to water pump failure, which is much more troublesome to repair. Once, I neglected it and only realized the coolant had degraded when I took it to the dealership, almost causing a serious issue. So my advice is to follow the manual, but if you frequently drive in harsh conditions—like long highway trips or extremely cold regions—it’s safer to shorten the interval to around 3 years. Either way, don’t skimp on this small expense; regular checks can save you from costly repairs later.
