Hello any advice please, I think I may have dodgy thermostat.

Noticed Engine running at about 79C I think it was higher than that previously,

also Exaust Filter Clean has come up a few times in last month, thats more than normal

 

If it is thermostat any idea price and how easy a chan ge is it

Thanks for any advice

 

 

 

 

79C on these is absolutely fine, they only go up beyond that if you are really razzing them. How many of your journeys are short trips? And is the engine getting up to temp on most of the journeys you are doing? In these colder temps the car requires a longer period to get up to temp and a longer period of being at temp to stop the dpf clogging.

4 hours ago, pilsudski said:

Noticed Engine running at about 79C I think it was higher than that previously,

The outside temperature was also previously higher  🤣

My Focus 2.0 EcoBlue is lucky to make it to 74^oC on a good day when the weather is cold. Modern diesels just don't get hot.

Modern engines in general don't get that hot

From what I've read here and elsewhere the direct injection petrols run hotter than normally-injected ones, the higher temperature leading to cracking of the header tank.

I know that diesels generally run cooler than petrol though.

3 hours ago, mjt said:

From what I've read here and elsewhere the direct injection petrols run hotter than normally-injected ones, the higher temperature leading to cracking of the header tank.

I know that diesels generally run cooler than petrol though.

Exactly especially as a diesel running hotter increases NOx emissions...

NOx is created during high cylinder temps.  But that doesn't have much effect on the coolant temperature.  It's certainly not the reason that diesels run cooler.

Coolant temp has been set to ~90c for decades.  Basically warm enough to prevent energy being wasted heating the block, but cool enough not to boil which would create air pockets and hotspots.

Now that we have computer modelling, manufacturers can fine tune their coolant temps to provide maximum efficiency, so stats are often set closer to 80c on diesels nowadays, after considerable lab testing.