Fiat Panda 1.2 2004 cooling conundrum

[davepoth]

Possibly a bit low rent for these parts but let's give it a go.

Work colleague's car was acting odd. On start up the car would warm up, heater was nice and hot, everything was fine. When it got to operating temperature it started blowing cold. As soon as she got onto the motorway, the heater ran hot again.

I topped it up with water and coolant at lunchtime - I only had just over a litre to hand and it took all of that and I don't think it's quite there yet - and it seems much better.

What I'm thinking was going on was that when the thermostat was closed the coolant circuit excluding the radiator was small enough to keep water in the heater matrix, but when the thermostat opened and water got pumped into the radiator the level in the system overall dropped, drying the heater matrix out until the airflow cooled the engine enough to close the thermostat.

Does that sound plausible?

What's probably more important is that I don't know the FIRE engine too well. How tolerant are they of coolant abuse? I guess it's got a leaky head gasket (a bit stinky at full throttle on the motorway) but is that going to fail catastrophically next week or will it limp on for a while with a bit more care to the coolant level?

[Mound Dawg]

I had something similar on an old Mk1 Punto 1.2 I ran as a daily, head gasket was gone, car had lost enough coolant that it didn't get round to the heater all the time although I think that the higher speeds (ok, 70 mph 3500 rpm) on the motorway were enough to throw some hot water into the heater circuit.

Fill it right up and it should be ok (for a while if the gasket's gone) but when the level drops again the same thing will happen.

It's not all bad news though, if it is the head gasket the sparts are cheap and the job's a pice of p155 on these Fire motors.

[davepoth]

Sounds about right - topped it up last week and it doesn't seem to be dropping too fast which is a good sign.

Sat in stop-start traffic this evening the temperature gauge was very slowly creeping up past 1/2 on its way to 5/8, but the fan did not cut in.

I can't find any concrete info anywhere as to when the fan is supposed start up - does anyone have an idea? If it's broken I guess it'd be a wise idea to have it fixed before the weather turns warm...

[Matthen]

davepoth said:

Sounds about right - topped it up last week and it doesn't seem to be dropping too fast which is a good sign.

Sat in stop-start traffic this evening the temperature gauge was very slowly creeping up past 1/2 on its way to 5/8, but the fan did not cut in.

I can't find any concrete info anywhere as to when the fan is supposed start up - does anyone have an idea? If it's broken I guess it'd be a wise idea to have it fixed before the weather turns warm...

Our pandas temperature dial never climbed over bang on half, but from what i've read, middle can be anything that the ECU considers "normal." If the needle is pointing over half, there is a problem - either a broken fan or a knackered head gasket.