04 Ford Fiesta - Overheating

Hi there, looking for advice on what could be wrong with my car. Old car so trying to figure out if worth fixing it. 60k on the clock

  • EML on
  • Severe coolant loss (having to top up antifreeze every drive, internal leakage by the looks of things as no visible leaks)
  • No engine power loss
  • White vapor coming from right side of bonnet
  • Oil looks fine (recently serviced)
  • No smoke from exhaust as far as I can tell
  • Hissing from expansion tank, small cracks surrounding the cap

Remove the radiator cap when the engine cold.

Start the engine, and as it idles watch the coolant in the radiator.

If bubbles form in the coolant, he engine has a blown head gasket.


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Symptoms point to a leaking head gasket. An expensive repair unless you do it yourself. There could be other internal damage to the engine as a consequence of coolant loss and overheating.

The white vapor suggests some coolant steam is being expelled to the outside of the gasket. The hissing indicates engine compression getting into the cooling system’s plumbing - another indication of a head leak.

Can you get a readout of what is causing the EML (AKA CEL, Check Engine Light, or MIL, Malfunction Indicator Light)? This does not always come on in case of a head gasket leak, but may give a clue as to what’s going on.

Just went and checked. There are no bubbles

What else causes substantial coolant leakage?

Car has been plugged in and diagnostic says cylinder 3 misfire. Orange check engine light is on

Then you may have a bad thermostat that’s stuck closed.


needs to be addressed. if the system does not hold pressure the engine will overheat, and you will lose coolant. I am not familiar with your specific car, but you can be losing coolant through the overflow tube if it has one.

Will a pressure test confirm this? If the thermostat is stuck closed, then where is all the coolant going?

No.A pressure test won’t reveal if the thermostat is stuck closed.

Remove the the thermostat and boil it water to see if it opens,


Cylinder 3 misfire is a clue to the location of the head gasket leak.