Citroen C5 Thermostat Problems

My car was overheating. I filled up with coolant but after about a 10 mile journey the coolant container was empty. I filled it up again and this time kept the engine running while watching the coolant. I noticed it started to boil and seem...

have replaced header tank cap because rubber seal had poped off and water was coming out i seeem to be getting air into water system as i can bleed air daily from thermostate housig just a small amount approx 2 to 3 seconds of bleeding

HI I AM HAVING PROBLEMS WITH MY C5 ESTATE HDI..02 PLATE......START CAR UP DRIVING ALONG AND THE TEMPERATURE GAUGE ON THE DASH BOARD GOES DOWN TO THE 2 COLD MARKERS THEN SLOWLY RETURNS TO THE MIDDLE OF THE TEMPARATURE GUAGE ....AND JUST REPE...