Hi,

For a while I thought I might have something wrong with the coolant system in my 05 Focus. When you open the bonnet the reservoir looks empty, as such about 5 months ago I filled it up with coolant and water, and forgot about it. After a while I noticed the fan was coming on every time I finished a journey, so I popped the bonnet and the reservoir was empty again, so I filled it up again, and forgot about it, again.

Then after a while the fan started come on after every journey, again. Popped bonnet, reservoir empty so I asked a colleague and he suggested running the car for 20 mins with the reservoir cap off, incase there was an air bubble. I Did this and after a a few mins hot coolant started flowing through the 'top pipe' back into the reservoir, which filled up to the min line and after a short while almost all disappeared through the 'bottom pipe'. This carried on, until I switch the engine on at which point all the coolant flowed out through that 'bottom pipe', again.

My first question is, is this the normal operation of the coolant system? And if so where has all the extra coolant gone from when I was filling the empty reservoir up? Or, should there always be coolant in the reservoir, at least up to the min level?

Thanks! :-)

Sounds like the system needs a bleed. Leave the cap off and add coolant until it stays at a constant level. It should always be between the Max and Min marks.

As for where the coolant has gone, you could have a small leak. This would also explain how the air bubbles are getting in to the system.