Peugeot 206cc overheating under load

[mik_se7]

Hi everyone,
I'm a bit stuck at diagnosing what is wrong with the Peugeot it sounds and drives without a hick up but yesterday it started to over heat.
The water had gone from the bottle so i filled it up, i ran the engine and just passed 90 on the heat gauge the fan kicks in and the engine cools down, but when driving it home the engine reaches 90 and then keeps gong to the red line where the car was stopped and switched off to cool down as not to cause engine damage.
I then drained some of the water to check the thermostat which was open and i had replaced this recently (about 8 months ago).
I then refitted the thermostat and refilled the water bottle and put fresh coolant in it and ran the engine with the cap off the water bottle to let out any air locks.
again the engine stayed cool but once driving it started to rise again but i got it home ok and left the engine to cool right down.
last night i checked the water bottle it was low but not empty so i topped it up, i then checked the oil cap to see if there was any mayo or water residue (indication of blown head gasket) but all was clear, i then ran the engine again first with the cap off just in case any air locks might still remain and then with the cap on as the water didn't move and the car stayed below 90 the whole time.
I even turned on the heating inside the car full whack and it was barely getting hot so i thought air lock and all is well...

This morning i drove the car to work (mix of local driving and motorway) and it preformed as it should the temp rose hit 90 and then cooled down until i reached work and the gauge then started to rise towards the red line again.

suggestions online are maybe the water pump but when i took the thermostat out the water pumped out without issue, the next suggestion is the radiator being blocked which i havent tested yet. does anyone else have any ideas?

thanks
Michael

[Capncol]

Are you using the bleed valves to expel the air?

[mik_se7]

No I haven't used the bleed valves to expel the air, what would be the procedure for doing this is it open when the engine is cold and the run for a while and close the valve?

[mik_se7]

its ok i found a procedure on how to do it on this forum so i shall try it and see if it works.

[gazza82]

Could be a failing temperature sensor. It's is relatively easy to change as it plugs into the thermostat housing. Had to do one in the past that claimed my engine was overheating, but it didn't feel hotter than usual.

[mik_se7]

Update: I bled the valve at the back there was a small hiss and then water flowed and since then it hasn't over heated it reaches 100 on the temp gauge and the fan and thermostat kick in and the temp drops, i think i'm going to replace the temp sensor anyway just to make 100% sure because as gazza82 said the engine didn't seem any hotter and the temp readings were a bit inconsistent.

thanks for all your help guys

[mik_se7]

Update: I drove home in the 206cc on friday and it went up past 100 so i knew it wasn't an airlock so this weekend it emptied all the coolant flushed through the system until the water ran clear, I then took off the radiator and flushed that (lots of rusty gunk), the radiator didn't look in the best condition and even though it wasn't blocked for £35 for a new one i replaced it a long with the coolant temperature sensor. next i removed the timing belt and took out the water pump to find the blade had worn away (there was my problem it wasn't pumping the water properly). Anyway new pump fitted and new timing belt, next new green 50/50 coolant put in and started the engine which purred like a kitten with the heating up full, i checked the bleed valve and after 5 minutes i put the coolant bottle cap on and the temp gauge stayed about 70 -80 the whole time. i then took it for a drive for 10 minutes and left it to cool down for about 5 hours.
I topped up the coolant and all appears to beat working perfectly.
thanks for all your help guys

[GrandadMonkey]

That's a job well done Michael, back to basics always works!