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Ford Fiesta: reg..engine keeps overheating...radiator air

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Hi, I have an "S" reg Ford Fiesta ghia 1.25. The engine keeps overheating. I have had a new radiator, new water pump, new thermostate, new pipe as theone into the engine from the radiator blew and also a new heater mechanism that has the two pipes running to it with hot air from the engine. I have been told the head gaskett is fine, so what can it be, i am at a loss
Hi there , good evening to you

Ok when does the engine overheat
In the morning /after /during driving Etc
Are all pipes /hoses hot in the engine bay etc
Do you get hot /cold air inside the vehicle

Regards Brian

Customer: replied 5 years ago.
Hi, the pipes to the engine from the radiator is very hot, the pipes to the heater are hot too. also if you look at where the coolent is then you have a slim pipe that runs out to the left this is hot too. Its overheated twice since all the new parts were put on but i have managed to put the heater in the car on and the engine colled, Today the heater blew cold and i had tio keep switching the heater fan on and off before it decided to blow hot air
Hi there , ok this fault could lie with one of a few things

Ok from experience I would suspect a blocked heater matrix (common on the older fiesta )
Usually if the coolant is of a brown type colour due to rust /poor servicing of the coolant system this ends up blocking the heater matrix up and thus overheats the engine
This is usalky comin ones with a brown colour noticeable in the resivoir and contaminated the full coolant system and the matrix catches most the rust /debris
An easy way to check this is to by pass the heater matrix
Just join the 2 rear coolant hoses that leave the heater control valve (the valve with 4hoses going to it on the bulkhead ) And run the vehicle (you will only get cold air in the vehicle when doing this

Other faults can be faulty coolant resivoir caps (a lot of people overlook these ) these should be checked every service for ANY deteriation of the seal
When the caps faulty (losing pressure but not water the engine usalky overheats at around 100-105 degrees ) because s if the coolant system isn't pressurised it boils up at a lower temperature

Also you don't mention if the cooling fan is working as this is imperative to correctly cooling the engine coolant down

If you need anymore help or advice on this issue please let me know
I hope you have been completely satisfied with my answer/advice As Customer satisfaction is my priority
Kind regards XXXXX XXXXX and have a nice evening


Customer: replied 5 years ago.
Hi, I have changed the resiviour cap and also the fan cuts in. The mechanic is suggesting flushing the engine with some kind of cleaner to get rid of rust and debris build up, is this a sensible thing to do?
Hi there ,
Ok flushing the system can help but as I said if the rust /brown colur /debris is excessive it can choke the heater matrix causing your overheating concern (If this is the case then replace the matrix
The good news is you can replace the matrix from under the bonnet unlike most vehicles where the dash needs to come out )
As you said the vehicles air went cold this is a tell take sign of a blocked matrix as the hot coolant can flow through it to give you warm air
A blockage in this matrix can also cause excess pressure in the system causing hoses and sometimes the coolant resivoir to split at the seams

Depending on how bad the rust /debris is a flushed be rendered useless
I have seen these vehicles needing every hose replaced due to hardening of the hose because of the rust /debris
By pass the matrix first to clarify this is the fault which I strongly suspect it will be

If you need anymore help or advice on this issue please let me know
I hope you have been completely satisfied with my answer/advice As Customer satisfaction is my priority
Kind regards XXXXX XXXXX and have a nice evening

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