Hi all need to pick your brains

Just had the head gasket done on my 1.6 petrol focus. Needed doing. Car was overheating under motorway speeds. Also the thermostat and temp sensor have been renewed

Just wanted to know what kind of temps the car should run at. Coolant temperature at idle is 108 degrees and goes upto 120 when driving. I'm worried this is to high and the work I had done hasn't solved the problem

thats the head temp if youre reading it off the dash display the focus is unlikely to have needed a head gasket done to be honest as overheating is usually down to a faulty thermostat or radiator pressure cap or issue in the cooling pipework ford designed the engine to run on 2 cylinders if it was to overheat and youde know the car would hit limp mode and not drive above 40mph or rev high either if youre reading the head temp the coolant will be 40 degrees below what that says so 120 head temp is 80 degrees engine temp the coolant temp is shown on the temp gauge on the dash clocks

sounds to me like you didnt have a gasket problemn in the first place they are rare even on the older focus

I'm not reading it off the dash. Have obd adaptor and an app on my phone that tells me it's the coolant temperature so I assume that's it's the coolant.

personally i dont trust them what does the head temp say on the dash readout assuming it is getting hot has the pressure cap been changed its usually the main cause of overheating

simple checks has the water pump been done on a 2002 it would be needing it by now a head gasket is the last option to be honest always start withy the thermostat then the sensors coolant cap etc

Was the radiator checked for any blockages?

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Well when the app gets to 127 degrees and flashes at me the temp gauge on the car shoots up so I think it's pretty accurate.

I managed to crawl home and I checked the radiator. The in pipe was red hot and the out pipe was stone cold. Not even luke warm. Even when the fans kicked in.

Also think the head gasket was on its way out anyway. Coolant had loads of oil in it and the oil had water

And yes water pump/timing belt already done. Car is on 108k miles

oil in the water water in the oil can also be from the oil cooler which is fitted to the front of the engine and can make it look like a head gasket a simple compression test will show this but hot oil entering the coolant from the cooler will cause this to happen also so it may not be the head gasket

Sounds like blocked radiator and coolant not able to circulate effectively.

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Change the expansion tank cap before you spend any more money on it. You wouldn't believe the number of people who have head gaskets replaced because the cap wasn't holding the pressure.

Yeah I was thinking flushing the radiator, basically anything that only costs time first.

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Thanks for the help guys. Will buy a new expansion tank cap on my way to work tomorrow see if that helps. If not I'll work on unblocking the rad

Fitted a new cap on the expansion tank. Went for a drive but still got 125 degree reading on my phone and 103 off the dash reading. But with the new cap both hoses to the rad are now hot and steam hisses out when you loosen the cap.

Just worried about the heat reading still?

The system may need bleeding now as with poorly sealed cap air would of been dragged in.

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