Temperature and Slight Coolant Loss Query - W204 CDI

[Vx-Man-G]

Hi guys,

After a bit of advice please.

My has dad W204 2010 CDI.
He has been saying that he is noticing that the temperature goes up really quickly and always stays around the 100 degrees mark.
Also, he has noticed a slight coolant loss which is becoming more regular, but only slight, not bucket loads.
He has also said that when he goes to add more coolant in, he has noticed that the coolant cap is always slightly loose, despite him making sure its tight when he last tops up.
The previous coolant cap was broken so we have replaced this 6 month ago.

There is no spillage below the car, nothing glaringly obvious leaking. Car heaters/blowers all work fine and plenty of cool and warm air.

Any pointers please?

Thanks.

 

[alexanderfoti]

Usually leak at the water pump, or on the seal around the fuel filter housing on the engine block side, stick your head under the covers with a torch and check those places

 

[Vx-Man-G]

Usually leak at the water pump, or on the seal around the fuel filter housing on the engine block side, stick your head under the covers with a torch and check those places

Where are both of these located?
Also where is the thermostat, could it be that?

 

[alexanderfoti]

Where are both of these located?
Also where is the thermostat, could it be that?

thermostat at front top of engine
water pump on the front of the engine with a belt on it
Fuel filter on top right hand side with 2 rubber hoses going to it, and a shiny metal top

 

[Vx-Man-G]

Bit of a frustrating update, so this morning the coolant check flashed up, and now we have oil inside the header tank again!!

Surely the oil cooler hasnt gone again? It was only replaced 2'ish years ago?!

 

[mioba]

Cant say if the oil cooler is toast without looking at it.

Which brand oil cooler was used last time and whom dome the work. MB have 2 years warranty on parts so you might be lucky.

 

[Vx-Man-G]

Cant say if the oil cooler is toast without looking at it.

Which brand oil cooler was used last time and whom dome the work. MB have 2 years warranty on parts so you might be lucky.

Genuienly have no idea.
Its back in the garage today, lets see what he says.