Coolant temperature sensor location?????

[captain1903]

Hello,
Does anyone have or know where I can get a diagram for the location of the coolant Temperature sensor for a vito 2013 w639 please. Many thanks

 

[VitoVanMan]

If your engine is an OM 646, its in the thermostat housing, which is situated on the cylinder head adjacent to the oil filter cover.
If you need to replace it , you will probably find it seized in the thermostat housing, if so when you buy a thermostat housing it comes with a new sensor and retaining clip. Also if like me, you will probably manage to shear at least one of the three M6 torx bolt heads off in the process. Or you may be lucky and it comes out in one piece.
As your vehicle is over ten years old, I would expect some galvanic corrosion to have taken place and it won't be the easy option, so be prepared for replacing the thermostat housing option.
As a matter of interest, why are you changing the engine coolant temperature sensor?

 

[captain1903]

Hello thanks for the advice, yes my plan is to change the coolant temperature sensor, I'm really hopeful that's it

 

[DREAMER NO2]

Look out for coolent escaping as you screw the sensor out . Do it on a cold engine and you might get away without coolent escape.

 

[captain1903]

Thank you I will keep an eye out

 

[VitoVanMan]

I have spoken with an MB colleague and it appears you should have the OM 651 engine in your vehicle and the thermostat housing is plastic on these, so it should be a straight forward extraction, unlike mine where the housing is an aluminium casting and badly corroded. So hopefully just some release agent, like penetrating oil or silicone lubrication spray. should do the trick.
Just watch out for the retaining clip having a mind of its own and disappearing into the engine bay.
I drained out via the bottom radiator drain tap and collected about 4 litres of coolant to avoid any unnecessary loss.

 

[captain1903]

That's great advice thanks. I'll tie string on the clip to stop it disappearing

 

[captain1903]

Thanks everyone for your advice, I managed to fit the new sensor, out of limp mode and temperature looking normal. The advice about not losing coolant was helpful, I swapped them quickly and managed to hardly lose any, also the advice about the 'clip of death'.. did disappear for little while, but found it and sorted.
Thanks again all

 

[DAJthebabe]

Hi guys, does the sensor unscrew or just pull out?

I'm just waiting to find it's location before having a go at replacing mine, looks like it's a push fit held in with clip (a new clip is supplied with the new CS)

Thank you!

 

[captain1903]

Hello, yes it's a push in with a clip, be careful with the clip. Location is easy when you take the airbox and engine cover off, the green circled is the coolant temp sensor (goes into thermostat)
My thermostat is plastic which apparently is the best as it does corrode. But was still a pain to get it out, have the new one to hand, so you can swap as quickly as possible.