The speedometer sometimes dies or swings merrily to its stop. I have found that stopping the car and applying full lock clears this fault, so this indicates there is some loose connection rather than a fatal fault.
When cold there is a knocking from around the water pump area, this has been happening for a year and clears as soon as engine is up to temperature.
The 406 is very comfortable and is equipped with power steering, air-conditioning, electric windows and airbags for driver and passenger.
The biggest disappointment is a flat performance compared to a 405 diesel and a worse fuel consumption, usually below 40 miles per gallon. My best has been 45 miles per gallon and the worst 34 miles per gallon.
If you are buying a 406 Diesel, go for the 2.1 or the newer Hdi's, the original 1.9 was painfully slow, especially when overtaking or pulling away7 from lights etc.
The extra 200 cc on the 2.1 doesn't sound like it should make much difference, but in practice it's a completely different engine, a fast car and a joy to drive.