406 coolant leaking - Carman55
I Have a 1.9dt 1998 406 which is leaking coolant slowly, it goes from max to the warning light coming on every 1k (3 weeks) any ideas where i could start looking for the leak? should i just carry on topping it up or could their be a bigger problem that is causing this to happen
406 coolant leaking - 659FBE
First stop radiator - very poor quality OE components on these cars. Better quality replacements from GSF. Be particularly careful to ensure that the cooling system is always fully vented of air - it's not always easy to do this on XUD engined vehicles. A squash bottle with the base cut off and the neck sealed to the car's filler will help, but it's a messy business. Once you have fixed the leak, use 50% concentration OE antifreeze plus clean rainwater and flush and change every 3 years, otherwise head gasket looms. These vehicles will not tolerate bodges in the cooling department - leave the radweld on the shelf.

659.
406 coolant leaking - Reggie
The other possibility is that the headgasket is on its way out and if so the leak will get worse until it fails. I think it's a case of eliminating leaks from anywhere else.

I have a 406 2.1td and that has started loosing a small amount of fluid (less than yours) and I could smell anti-freeze for a few weeks when the car had been run and I was out of the car, but I couldn't see any leak or anti-freeze staining anywhere, that is until last week, when I saw a small collection of fluid below the rad, which proved to be anti-freeze.

The point I'm making is sometimes it's hard to see where there is a leak. I had suspected my headgasket, but logic said that as I could smell antifreeze that there was an external leak somewhere, and so it eventually proved, but I couln't understand why I couldn't easily see the leak.

Reggie
406 coolant leaking - rg
Forte produce an excellent radiator sealant which stays active in the system and does not gum anything up (apart from leaks).

It is used to great effect on Xantia matrices by my local cit indie.

rg