i draw that pipe, watch it now

[Ndelilio Nnko]

what are function of this pipe? it may cause heat in r4 if not open sometimes! or it may cause radiator to be boiled??

 

[r4-gen]

That's the air bleed valve, to let any trapped air out of the cooling system

 

[peterlaws]

Bleeding coolant system

If you have the plastic expansion bottle lift it higher than the heater matrix (heater radiator) and open/bleed this pipe.

 

[Ndelilio Nnko]

Thanks alot

I appreciate your help! Now l know how to maintaine my R4.