Leaking Coolant? Duff Sensor?

[Funkoid]

Complete novice that wants to learn more so be warned! I have a 1.6 Ford Escort 99 plate finese. The temp gauge hasn't worked for ever and a day and i've not really thought much about it, the car has always run well without any issues. However recently i've found myself topping up the coolant... think i've gone through around 1/2-1 litre in 6 months or so... i figure I have a leak and want to know where to look first!

There aren't any obvious patches on the driveway although i'm half convinced i've seen moisture coming from what I think is the gear box about a ft or two down the underside of the car nearer the passenger side?

....am I on the right track? Any pointers? Should I just scrap it now!

[lublin]

Complete novice that wants to learn more so be warned! I have a 1.6 Ford Escort 99 plate finese. The temp gauge hasn't worked for ever and a day and i've not really thought much about it, the car has always run well without any issues. However recently i've found myself topping up the coolant... think i've gone through around 1/2-1 litre in 6 months or so... i figure I have a leak and want to know where to look first!

There aren't any obvious patches on the driveway although i'm half convinced i've seen moisture coming from what I think is the gear box about a ft or two down the underside of the car nearer the passenger side?

....am I on the right track? Any pointers? Should I just scrap it now!

Are you filling the expansion tank to the top (Max line), because if you are then that's wrong, it should only be there when the engine is at normal temperature and if you fill it to that level it will drop back down, over a short time, to it's natural level where it will then stay.

If it's not just what I said above, then on a dry morning lift the bonnet and look for a damp patch on the radiator or on any of the hoses where they connect to anything. It could also be the head gasket but it sounds like, if it is this, it's a very small leak and so you might not get oil floating on top of the water in the expansion tank.

Make sure you replace the water with mixture and not straight water as this will weaken the mixture which prevents freezing in the Winter and helps cooling in the Summer.

If it's none of the above then take it to a garage and let them check it over.