When should I change the oil in my Astra?

After much deliberation I've finally changed my less than impressive Toyota Auris diesel for a new Vauxhall Astra. I decided to get the new 1.6 CDTI whisper diesel, which is proving to be a fantastic engine so far. I've had the car five months and covered 10,000 miles with a tank to tank economy of 68mpg without trying too hard. I want to change the oil every 12,000 miles as letting the car run to 20,000 before an oil change seems ridiculous. I noticed the car is fitted with an oil quality sensor and readout. It is currently showing 31%. Should I go by this indication or change the oil at 12,000 regardless?
The 1.6CDTI 110 is the one to get and our Real MPG figures confirm yours. The more powerful 136 engine uses a lot more diesel. I would change the oil and filter at 10,000 - 12,000 miles regardless of what the oil contamination indicator tells you. Test of the 1.6CDTI 136 here: www.honestjohn.co.uk/road-tests/vauxhall/vauxhall-.../
Answered by Honest John on

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