After not having any coolant for nearly 3 months today ive put some in I’ve had the car running for a good while got heat in the car lovely job but what is confusing me is the top radiator pipe is cold is there something I’m missing or being stupid ? 

Don't understand the comment "no coolant for 3 months"
Only thing I can say is does it need bleeding, more coolant (unless self bleeding) and was it just idling or actually under load (heater looks like it doesn't need bleeding)?

Sometimes there's an air lock which, if/when relieved will need topping up?

5 minutes ago, Shearers said:

Don't understand the comment "no coolant for 3 months"
Only thing I can say is does it need bleeding, more coolant (unless self bleeding) and was it just idling or actually under load (heater looks like it doesn't need bleeding)?

Sometimes there's an air lock which, if/when relieved will need topping up?

Cars been off the road but the car was idling 

So, why did you have to top it up?

How much did you put in?

How much do you think is in now?

Are there any signs of leaks either before or now?
Is there enough coolant to safely go for a short  run to see if any air lock will come out (e.g. when thermostat opens) - I can't be responsible if you do that!

Can anyone else suggest what is going on (and especially if this auto bleeds or needs something else doing?