Coolant temp sensor
 

Hi, does anyone know where this is on the 09> D5 engine? Cheers

On the thermostat housing. See the diagram in the linked web page.

https://www.matthewsvolvosite.com/fo...ic.php?t=71604

It's item #6

Thanks but I believe that is the single turbo D5 unit? Mine is the twin turbo with the weird thermostat housing tucked in right at the back of the engine next to the turbos. I'm presuming the sensor isnt on the stat housing (!) bloody hope not anyway. Ill have a bit more of a look in daylight when I can.

Think Ive found it. Its on the front of the engine on the plastic coolant housing (parts 10 and 15):

https://i.imgur.com/lVjbgEE.jpg

Sorry if I misled you! The CTS is a very underestimated component. A great deal relies on its accurate provision of data and even if it doesn't fail, deterioration of the accuracy of the temperature readings can cause problems with the fuelling of the engine, a bit like running with the choke always a little out or not having enough choke when the engine's cold. I think the two principles that apply to the CTS, like the thermostat, are that it should be routinely changed and that the replacement should be of the highest quality.