Airlock in Radiator?

[Chris Scott]

So, for every step of progress on my rebuild i seem to take two steps back!

When my car (1.8 Zetec) runs the top radiator hose gets hot - I’m taking this to mean thermostat is working.

However the radiator itself stays cold and the rad fan doesn’t come on - despite the engine approaching 100

i cracked the rad cap and coolant started to come out so the level is correct and it’s pressurising.

Could this be as simple as airlock in the radiator? And if so any tips on how to cure it?

[alanrichey]

Where is the sensor switch for the radiator fan ?   Top hose, Bottom hose, Radiator .....  ?

[IanS]

Have you got the right water pump? I believe there were 2 , one rotated clockwise and the other rotated anti-clockwise, which was fitted depende on fitment of aircon.

Is the impeller still attached to the drive shaft?

[Chris Scott]

Thanks both, Alan, the switch is in the radiator - previously the radiator got hot, i then changed the switch as a precaution - obviously losing coolant in the process - I’ve topped it up and this is the first time it’s run since. Hence why I think it could be airlock.

Ian - yes I’ve seen about the water pumps - all I’ve read suggests I have right one - and it did seem to work before - but certainly something I will look at as well 

 

[alanrichey]

Airlock is a good suggestion.   I actually got an airlock once that went to the top of the system, unfortunately that is where the water pump is located (Ridiculous Rover design) and it covered the pump so I lost all circulation and experienced similar symptoms to you.    You need to figure out where the highest point is and try and bleed it.  One trick is to jack up the front of the car so the top of the radiator is definately the highest point.

[Chris Scott]

On 10/29/2022 at 11:43 AM, alanrichey said:

Airlock is a good suggestion.   I actually got an airlock once that went to the top of the system, unfortunately that is where the water pump is located (Ridiculous Rover design) and it covered the pump so I lost all circulation and experienced similar symptoms to you.    You need to figure out where the highest point is and try and bleed it.  One trick is to jack up the front of the car so the top of the radiator is definately the highest point.

I have a feeling this is exactly what’s happened, the airlock is in/at the pump. Will Jack the front right up at the weekend