W212 coolant leak

[KingAky]

Hi

So my e250 has a coolant leak. Literally need to top it up after a day. Took it to my specialist who advised my water pump is leaking and that's the issue. Ordered the part and fitted. Had it back a day and put key in ignition & I still have a leak. So my question is, is there any common areas coolant leaks on the e250 edition 125?
Thanks

 

[Trickythemerc]

It could just be an airlock, after working on the cooling system it needs burping to get the air out. Could also be a faulty level sensor, run it for a couple of days and keep checking the level.

 

[KingAky]

It could just be an airlock, after working on the cooling system it needs burping to get the air out. Could also be a faulty level sensor, run it for a couple of days and keep checking the level.

I've had it back a day and the coolant level has definitely dropped. So defo seems like a leak still in there.

 

[AMGeed]

Run it up to temperature and check the coolant filler bottle and associated pipework for leaks.
My E class had a pinprick hole in the coolant reservoir that didn't leak until up to temperature and under pressure.

Was the new water pump a genuine Mercedes part?
When the engine is cool, slip your hand under the water pump and check its not leaking there.
I'm surprised your specialist didn't check for leaks after fitting the pump.

 

[KingAky]

Run it up to temperature and check the coolant filler bottle and associated pipework for leaks.
My E class had a pinprick hole in the coolant reservoir that didn't leak until up to temperature and under pressure.

Was the new water pump a genuine Mercedes part?
When the engine is cool, slip your hand under the water pump and check its not leaking there.
I'm surprised your specialist didn't check for leaks after fitting the pump.

Yes it was a genuine Mercedes part. Had to go to Mercedes as they were not answering any calls due to their systems being down supposedly. So I spoke to my specialist and he said he checked everything including the fuel filter area and I can't remember exactly what he said but summat to do with air intake/clearance. For me to run it a few days and it should be fine as there was no other leaks. I shall see after a few days.

 

[Jobsworth]

Did they just change the pump or the back housing too? I always replace the pump and the back housing as well because I’ve seen hairline cracks in the back housing

 

[KingAky]

Did they just change the pump or the back housing too? I always replace the pump and the back housing as well because I’ve seen hairline cracks in the back housing

Yes they changed the full waterpump and the backhousing as originally there was also a leak there. Will post an update after a few days.

 

[WilliamParsons]

Checking for leaks in the coolant system after a water pump replacement is a crucial step in ensuring that the repair was successful. If you suspect a leak, it's essential to investigate it further. Here are some steps you can take:

1. Run the Engine: As you mentioned, run the engine up to temperature and closely inspect the coolant filler bottle and associated pipework for any signs of leaks.
2. Check the Water Pump: Feel around the water pump when the engine is cool to check for any signs of leakage. This is an important area to inspect since a leaking water pump can lead to coolant loss.
3. Inspect the Coolant Reservoir: As you experienced with your E-Class, even small pinprick holes in the coolant reservoir can cause issues when the engine is warm and under pressure. Inspect the coolant reservoir carefully.
4. Verify the Water Pump Source: If you find a leak or suspect one, ensure that the new water pump installed is a genuine Mercedes part and has been installed correctly. A poorly installed or low-quality water pump can lead to issues.
5. Consult Your Specialist: Reach out to the specialist who performed the water pump replacement and inform them of your concerns. They should inspect the vehicle and address any issues if the repair was not completed correctly.

Regularly checking the coolant system for leaks and addressing them promptly is essential for the proper functioning of your vehicle's cooling system and to prevent overheating or damage to the engine.

Run it up to temperature and check the coolant filler bottle and associated pipework for leaks.
My E class had a pinprick hole in the coolant reservoir that didn't leak until up to temperature and under pressure.

Was the new water pump a genuine Mercedes part?
When the engine is cool, slip your hand under the water pump and check its not leaking there.
I'm surprised your specialist didn't check for leaks after fitting the pump.

 

[AMGeed]

Checking for leaks in the coolant system after a water pump replacement is a crucial step in ensuring that the repair was successful. If you suspect a leak, it's essential to investigate it further. Here are some steps you can take:

@ William.
You might want to edit your exact location?
Not a great idea to give your full address and postcode on an open forum.

 

[Major774]

Pressure test your coolant system.

I had a small leak from one of my connected hoses to the radiator, it only showed up when the system was under pressure.

I was losing coolant slowly over time. I must have loosened the connection when I previously worked on my car.

 

[mersum1es]

Fuel filter leg checked? Common place to fail on OM651...

 

[DanE350cdi]

Best way is as mentioned do a pressure check.

 

[KingAky]

Thank you everyone for your responses. Much love. I can confirm it has all resolved. I just needed to take it for a drive to get the car up to temperature. I guess my specialist forgot or was too busy to do that. Thank you again