Temp Guage Erratic/ Overheat ? Help Pls

[digistar]

Hi , i own a 2000 plate 1.6s zetec focus and am at a loss in trying to resolve my issue with the car i own , im wondering if any of you guys have had this problem and come to the conclusion in fixing this and saving my mind. I have read a previous forum post regarding this with another members post but to no avail. the temp guage shoots over to the red whenever i climb up on a slight to high hill and comes down if i take my foot off or slow down.

So far i have had the rework done by ford as in the coolant bypass hose that goes into the radiator, new cht sensor new coolant and flush , changed the thermostat twice .. the cabin is getting hot they have checked and theres no leaks, coolant is clean and im desperate to fix my lovely car that's immaculate and loved by me. if there is any more information i can give please ask

any help guys ? i would be grateful for any of your help as i dont want to part ex my car, and most of all solve this problem for us all here.

sarah x

[artscot79]

sounds like a broken fin on the water pump it will still be pumping but not enough hence the overheating when the engines under load

[wase16ll]

i know its been flushed, but it could be a partial blockage somewhere...had a similar problem recently with a vw,

i would run it up to temp, then check the hoses/rad etc carefully for any cool spots.

only way i could find it on the vw was to strip as much of the cooling system down as possible and flush the parts individually as well as checking everything as i went along...turned out it was a blockage in bottom couple of bars in the rad and a small restrictor valve in a by pass hose that came off the head behind the stat...all caused by a previous use of a radiator leak sealant.

[digistar]

thanks for your replies :) i forgot to add that i had the water pump changed too. just been thinking about that i know a couple of the rubber coolant pipes off the bottle had been changed also as they had become softish kind of floppy and not like the other pipes on the car if this is of any other help ?

sarah x

[wase16ll]

does the heater temp remain consistently hot if left to idle for 5 mins when engine is up to temperature and heater fan on mid/high setting...

if the air from heater becomes noticably cooler after a few minutes idling, then gets hotter again once revs are raised for a few minutes...then that indicates air in the system or a circulation problem.

i'm still leaning towards a blockage somewhere

[artscot79]

has anyone replaced the coolant expansion cap on the tank???? this would prevent the pressure building up and cause the boiling point to lower causing the over heating they are about a tenner so well worth changing and in a few cases ive dealt with was all that actually needed done yet garages rarely test them

[digistar]

thank you for your replies it all helps me :) furthermore to this the mechanic had drilled a small hole in the thermostat and i had run it , yes it seems better but after a good heat up it still indicates high upon driving uphill but cools down quickly going down hill, the fan doesn't seem to come on like as it did before all the time so there is improvement here, but i do know that this method isnt the best way to solve this, i am leaning towards wasel1611 post of a possible blockage somewhere as it only happens when its doing over 60 it seems to be restricting somewhere. i will try another cap tho artscot.

sarah x