I have a Focus Ghia 1.8 TDI (2007). The cylinder cooling water temperature appears to reach about 88oC only after very long engine run and seem to drop back. If my understanding is right the cooling water temperature should be about 90oC and should reach this setting pretty fast in order to protect the engine from cold corrosion and for best fule economy. My attempts to get the correct temperature setting through the Ford service centres had been futile. Much appreciate feed back similar experience and suggestions.

Mine takes ages to reach full running temperature and always has.

I have a Focus Ghia 1.8 TDI (2007). The cylinder cooling water temperature appears to reach about 88oC only after very long engine run and seem to drop back. If my understanding is right the cooling water temperature should be about 90oC and should reach this setting pretty fast in order to protect the engine from cold corrosion and for best fule economy. My attempts to get the correct temperature setting through the Ford service centres had been futile. Much appreciate feed back similar experience and suggestions.

Have you just bought the car or is this a problem that has just occurred? Engines obviously take longer to warm up this time of year especially if they're not garaged. How much does it drop back? 88 degrees is close enough to 90 - I presume it drops back further than that! Diesels run hotter than petrol engines so you are right to raise this issue - if it gets much lower than about 80/85 degrees then it needs sorting. If so then your problem sounds like a knackered thermostat. Cheap to fix and easy to sort yourself if you know one end of a spanner from another! Good luck.........