late bay supplementary heater blower pipes

My (1700) type 4 late bay does not have any pipes connected to the supplementary heater blower fitted above the engine.

Are these important and what exactly do they do?

thanks

 

they route the air sent from the accesory fan over the exchangers to assist in heating/demisting while the engine fan isn't running at a fast speed such as on tickover, if you don't have them fitted block the risers to stop hot air rising into your engine bay.

 

what he said. Important to block these off as if not hot air is blown into the engine compartment and it will make your engine run hotter!

 

Not at all expensive to replace, I recently replace mine. About £7 each from Heritage.