There seems to be a coolant leak in the W212 vehicle.

[Geek2232]

Greetings.

The e250 vehicle in question is experiencing a coolant leak. It is necessary to replenish the supply during a 24-hour period. I spoke with an expert who determined that the cause of the problem is a leaky water pump. The component was procured and subsequently installed. Upon its return, I inserted the key into the ignition, only to discover that the leak persists. My inquiry pertains to the identification of prevalent locations for coolant leaks in the e250 version 125.
We express our gratitude for your input.

[CodeCrusader]

The observed phenomenon may be attributed to the presence of an airlock inside the system. Following maintenance activities on the cooling system, it is necessary to perform a burping procedure in order to eliminate trapped air. Another potential cause for the issue might be a malfunctioning level sensor. To further investigate this possibility, it is recommended to operate the system for a consecutive period of several days while consistently monitoring the fluid level.

[Geek2232]

After one day of use, there has been a noticeable decrease in the coolant level. It seems that there is still a leak present.

[TechWhiz]

Raise the temperature to the desired level and inspect the coolant filling bottle and its corresponding piping for any potential leaks.
In my electronic class, there was a minute puncture in the coolant reservoir that remained impermeable until reaching the appropriate temperature and being subjected to pressure.

Was the recently installed water pump an authentic component manufactured by Mercedes?
When the temperature of the engine has sufficiently decreased, cautiously place your palm underneath the water pump to assess the absence of any leakage in that area.
I am taken aback by the omission of a leak inspection by the professional subsequent to the installation of the pump.

[Geek2232]

Indeed, the item in question was an authentic Mercedes component. I had to visit the Mercedes dealership since they were unresponsive to phone calls, purportedly due to technical difficulties with their systems. I spoke with my expert who thoroughly examined many components, including the fuel filter region. Although I cannot recall the precise details, he mentioned a potential connection to the air intake or clearance. In order to ensure its proper functioning, it is advisable to operate the system for a few days, since no more leaks were detected. I will assess the situation in a few days.
 

[Paqngo]

Was the pump replaced or was the rear housing also modified? The practice of replacing both the pump and the rear housing is consistently undertaken due to the observation of hairline fractures in the latter component.

[Geek2232]

The water pump and rear housing were replaced due to a preexisting leak. I will provide an update subsequent to a few days.

[Matt865]

Verifying the absence of leaks in the coolant system subsequent to the replacement of the water pump is an essential measure to ascertain the efficacy of the repair. In the event that there is a suspicion of a leak, it is essential to conduct a thorough investigation. The following are a series of steps that may be undertaken:

    Operate the Engine: As previously indicated, begin the engine and allow it to reach its optimal temperature. Conduct a thorough examination of the coolant filling bottle and its corresponding piping to detect any indications of potential leakage.
    Inspect the Water Pump: To assess potential leakage, it is advisable to tactually examine the water pump while the engine is at a lower temperature. The examination of this particular domain has significance due to the potential consequences arising from a malfunctioning water pump, namely the depletion of coolant.
    Examine the Coolant Reservoir: As shown in the case of the E-Class vehicle, the presence of minuscule punctures in the coolant reservoir might give rise to complications when the engine is operating at elevated temperatures and subjected to increased pressure. Thoroughly examine the coolant reservoir.
    Validate the Source of the Water Pump. In the event of a leak or suspected leak, it is essential to verify the authenticity of the water pump being used by ensuring it is a genuine Mercedes component. Additionally, it is crucial to ascertain that the installation of this water pump has been executed accurately. The installation of a water pump that is done inadequately or the use of a water pump of substandard grade might result in several problems.
    It is advisable to get guidance from a qualified specialist. Contact the professional responsible for the water pump replacement and communicate your apprehensions. It is advisable to do a thorough inspection of the vehicle and promptly rectify any deficiencies in the event that the repair was not executed accurately.

It is important to conduct regular inspections of the coolant system in order to identify and swiftly rectify any potential leaks. This practice is crucial for ensuring the optimal operation of the vehicle's cooling system and mitigating the risk of engine overheating or damage.

[Paqngo]

It is advisable to consider revising the specific details of your location.
It is not advisable to disclose one's whole address and postal code on a publicly accessible forum.

[CyberNinja]

Conduct a pressure test on the coolant system.

A little leakage was seen in one of the hoses linked to the radiator, which became apparent only during periods of system pressurization.

There was a gradual loss of coolant seen over a period of time. It is likely that the connection was inadvertently loosened during a prior maintenance session on my vehicle.

[BEERMAN]

Has the fuel filter been inspected? One often seen area of failure in the OM651 engine is...

[MrGreedy]

The most effective approach is doing a pressure examination, as previously indicated.