W204 thermostat issues

[BluBlur]

Hi guys,

My beloved 2012 C180 is reaching 120,000km mileage. So far no big issues except for CEL in March when I was driving back to Singapore along NSH.

 

I made a detour to Malacca (MBSA) to check the error, they found a coolant fault which may resolve with a software update. They cleared the light and asked me to follow up with C&C. Then I took no action since the major service is almost due anyway, and the CEL didn't appear again with driving in Singapore.

I also observed that the temperature gauge on my dashboard has been unusually hovering lower at 80 degrees C even if I drive hard. I'm not sure when exactly it started but I'm pretty sure the temperature would read 90 degrees C normally for the past few years of ownership, unless weather is very cold.

 

Come last week before the major service, I made another run to KL and sure enough the CEL came back again. Back at C&C, the SA informed of a possible temperature sensor fault, so maybe need to replace the electronic item with the sensor (i guess this is the thermostat housing). Any similar experience from guys here and how you resolved it? Thanks.

[kepiting1sg]

Yes!

The usual running temperature is around 90 degC.

The CnC SA could be right!

Why not get a 2nd opinion from a reliable MB workshop.

These are the usual workshops I frequent for my MB issues

1. Optimawerk

2.AutoSpritze

3. TLS Auto

4. Ignite Performance Lab

 

[BluBlur]

Thanks!

the error code is P0128 - guess i hit a “known” problem as Google threw up multiple hits.

Will plan a change of thermostat housing along with the coolant since it’s due for major service. Update back later.

[BluBlur]

Update - did the thermostat housing and coolant change together, since removing the thermostat housing also causes quite a spillage of the coolant.
And removing the thermostat was quite a chore... saw the mechanic having to remove the air filter box and manifold before getting to the thermostat housing.

The cost with labour was ten blue notes with a small change.

Now the temperature gauge reads 90 deg C - no more 80. I'm happy now...

I planned a road trip to KL in Aug, hope no more CEL during the long drive. If I don't post again, it's good news. Cheers all.

[kepiting1sg]

Glad to know you've your problem solved!

[Oscar]

Hi, does anyone know if you can just replace the coolant temperature sensor, without replacing the entire thermostat housing (about $400+)?

C&C will only want to change the whole thermostat housing. I don't know if anyone has done it in local workshops, but seems like its very easy to just change the sensor only which is what most in the west will do https://www.pelicanparts.com/techarticles/Mercedes-W204/37-WATER-Coolant_Temperature_Sensor_Replacement/37-WATER-Coolant_Temperature_Sensor_Replacement.htm. Of course, not much money to make the workshops i guess.

But just curious if anyone has changed their coolant sensor only in Singapore? Mine is a C-Class 1.6 Turbo 2013 W204