The big question thread

[Dum-Dum]

I would of thought that as the rad has a top pipe and a bottom pipe then for the best efficiency the top pipe should be the inlet for hot water and the bottom should be outlet for cold (and back round to the water pump) as heat rises

Rad? He asked about the matrix...

No Shit Sherlock! But as the matrix is connected to the rad via the rest of the coolant system then once you have worked out what way one of the big bits flows you can work out the little bits.

Hes saying the matrix hoses are the other way round. Would it not make sense to have to feed to the matrix coming from the block to then use some of the heat in the cabin before being cooled by the rad? I guess either way would make sense.

That does make sense in a way but as coolant doesn't really flow through the rad till the thermostat opens the only cooling is done by the matrix so any water in it would be warm.

Might get the IR thermometer out one day and measure the temp drop across the matrix and rad.