1.6 overheats only at 65mph plus
shoots into the red almost straight away and comes down virtually as soon as i slow down

not losing coolant
not running rough
just had new instrument cluster
no steam or smoking
no white smoke or liquid from exhaust

Any ideas

thanks in advance

Check and poss replace thermostat

edit ..you sure your not looking at the rev counter ;-0

coolant pump failing.
airlock in the system.
thermostat stuck.

Blockage in front of radiator? Plastic bag, leaves etc?

all the vents in the car work apart from the one by the drivers door ,would that indicate anything ?

When the needle goes into the red does the hot air from the blower get really hot?

Yeh pipes come off….the vent that is

heat seems normal when it pops into the red

I presume you have heck your oil level too? Otherwise as others have said stuck thermostat sound possible. cheap and easy to do.

Hmm, overheating cars usually spew very hot air out – but if it has fancy climatronic whatnot it might not do that.

oil is good ,it doesnt seem to be overheating just that the gauge says it is

Dodgy temp sender …but that usually plays havoc with the engine managment/fueling

seems to run great even when light comes on

ok …put sticker over temp gauge then …problem solved… 😀

Some cars have two temperature senders, one for the ECU and another for the gauge. Perhaps the gauge sender is borked?

Top speed – 65mph? Living the dream 😕

well it is not low speed is it !

I’d want to know if it was load related or solely speed related. If it were a severely blocked rad I’d expect the heat not to come down so fast. If the pump had failed/were failing I’d expect it not to come down so fast either as the coolant would be flowing even slower as you slow and the residual heat would continue to cook the coolant. Normally at 70mph most “normal” performance cars have far and away enough cooling for cruise without fans etc. Stuck stat seems to be about the best suggestion so far, if it’s jamming partially open you’ll get restricted fluid flow and possibly even cavitation problems in the pump which will trash your heat transfer at higher revs and as you come back down the flow will be sufficient to clear the heat happily.

But it’s late and I’m tired and I’ve probably missed something obvious.

wasn’t there a thermostat recall for the Focus 1.6 diseasel? Did yours miss out?

Are you sure the engine is actually overheating, or is the gauge just going up & down? I believe temp gauges are pretty heavily damped, so quick movement of the needle is more likely to be an electrical issue than an genuine reading.
Had something similar on our 323F, and it took me 8 months to track it down!
Temp needle would rise quickly, then drop quickly too. I was doing the usual things when the needle went high, ie heater on hot and blower on full. It was when I did this and then opened a window I noticed that the electric window made the temp needle drop!!
I went round everything- changed coolant, checked water pump, changed thermostat, changed gauge temp sender (as domwells27 says, there’s often 2 senders), pulled hair out. Then went round the engine bay checking for any earthing faults.
Eventually found one of the connectors on the main earth wire from the engine block had corroded and was showing a high resistance. The engine was thus trying to earth via the easiest path, up the temp gauge!!
Cleaned up the connections, problem solved!!

Hope that helps.
Rob

put it into diagnostic mode today round town it was on 103 – 105 c then on the motorway it went just past 120c …wrecking ones head !!!

drive faster