Air lock In Fiesta ?

[sh]

Hi
I fitted a new heater control valve on my wifes 2001 fiesta last weekend and now it seems that the fan runs more frequently and for longer than it used to.
Could it be an air lock and if so do I have to drain it down and refill it?
If so how do I refill it.Is there a specific way
Thanks

 

[Belle427]

have you checked the water level since re filling it?

 

[sh]

yes,and it is between min & max

 

[Nige F]

run it for a while with heater on full and the cap off of the water bottle

 

[sh]

I think it is definately an air lock.i can hear it coughing & spluttering in the pipes as it heats up.
To drain and refill do I remove bottom rad hose,flush through,then refill very slowly via the expansion tank ?

 

[^neo^]

Easy way to do it is to leave expansion cap off with engine running and keep the bollte filled to the brim. When the thermostat opens it will spew coolant out from the expansion tank, when it does this turn off engine and top up bottle if needed. as said above, make sure heater is set to hot (dont need fan going)
May be an idea to get the engine nice and warm first or you could be there ages waiting for thermostat to open in this weather

 

[sh]

what happens if thermostat is sticky and opens very late?

 

[Stivino]

You answered your own question. Take the bottom hose off, drain the system, flush it if you want then re-fill making sure the heater is bled. That's the proper way to do it, I wouldn't advise doing it any other way.

 

[sh]

How do I make sure that the heater is bled ?

 

[Stivino]

Disconnect the top heater hose & run the engine, if water comes out with no air bubbles, it's bled.

 

[sh]

If it has bubbles or doesn't come out how do i bleed it ?

 

[Stivino]

Disconnect the top heater hose & run the engine, when the water comes out with no air bubbles, it's bled. If no water comes out your water pump's kapoot.