98 mondy 2.0 zetec over heating issue , started yesterday on way home in traffic , never had a problem before yesterday ! noticed it was in the red after about 20 min of driviing at rush hour , pulled over and steam was coming from under the bonnet , let it cool down and had a look but water level seemed fine , got it home and let it cool , opened the expansion bottle cap and let the engine idle , temp gauge stayed normal , but every now and then there ws some bubbling in the expansion tank , like water being pushed back up the pipe into the tank , stayed fine so put the cap on and went round the block and it went straight to red ,still have HOT air blowing from the inside heaters , radiator top hose doesnt feel hot at all , and sounds like a gurggling in that pipe when engine is off , looked for a bleed valve but cannot find one , also noticed the temp needle goes down to middle when going straigh but as soon as i turn , left or right it goes to red again .
any one tell me were to find a bleed screw or what they think can be causing this ?
also some said these have to be lifted at the front and the rad cap removed and run for 15 - 20 min to bleed , and they wont bleed done on a flat surface ?

thanx in advance