Hello
The heater blows cold when hot is selected, despite new thermostat, bi valve checked over, the hoses either side of where they disappear under the bulk head are hotish, anyone help, winter is coming in the UK???

What year car? several systems.

Most likely problem is a heater valve.

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Hello
1991 230e saloon.

When you rev the car do you get heat in the cabin.

No but on inspection there is a cold draft in the flow of warm air as though fresh cold air is leaking into the duct.