Hi everybody, l have Peugeot 406 Diesel 2001-51 reg. Saloon LX, HDl 90, l have few questions to ask as under.
Question Details: 1) How to check coolant and fill radiator water?
2) The radio is not working as can listen ''SHOOO'' sound of the radio having CD player of Clarion Peugeot orginal fitted.?
3) How do l find or get owner manual of this model car(online or print or downloadable versions)?

l can answer the first question as a fellow 406 user/owner but l use a petrol one. l believe the radiator filling position is same for both models except for the first serious non A/C version. When u open the hood its onto ur left hand side right left to the ECU compartment box
You can not directly fill the radiator as in most of other cars but the reservoir. there r three filling caps onto ur left hand side as u open the hood.
From the front of the car
First one in blue color - its windshield washer reservoir
Second one in black color - its radiator coolant reservoir
Third one in red color - its power steering liquid reservoir.

For the radio matter yes u have to go to the dealer & l have not come across a download able user manual on internet for this so far. may be u can search web. l recommend to purchase an after market user manual such as Heynes