Ive seen HDi cars with over 350K miles and been told of them with more than that, so im sure if looked after they go and go.
My C5 has almost 117K miles and perfroms like a new car, no smoke, never uses oil or coolent, just superb. Very economical too.
Although im getting used to the 2.1TD Xm now, which is every bit as good to drive as the HDi, hmm i might even prefer the 2.1 engine. It seems just as economical, id actually say it sounds better on the go than the HDi. The 2.1TD has the same power as the C5 with 110bhp, but as i found out the other night the Xm is very slightly fater to 60! Which i was a bit surprised at.
I agree with oil changes, i do them every 6K miles on the HDis, including filter - why change the oil and not the filter

makes no sense.
As the HDis do quite a few miles, 6K miles is usually in around 4 months.
Some of our cars do very few miles, so i change the oil and filter every 6 months. Thats usually what i go by, every 6 months or 6K miles, depends on what they reach first.
I always use a forte engine flush in all of our cars on every oil change. And fuel system cleaners and clean the air intake too - this often works wonders.
You can never over service a car
