My car's heater only blows cold air - is a split expansion tank the likely cause?

I took my 2006 Ford Fiesta ST to a local garage as the heater only blows cold air. They've told me the expansion tank has split. They have the part on order but tell me it's going to be over £80, plus labour. Can you tell me whether this is in fact a legitimate explanation for why the heater only blows cold air and whether the price realistic?

Asked on 2 December 2017 by Liz Garside

Answered by Honest John
The expansion tank is the tank that collects the pressurised coolant and steam after it has been through the engine and, if it has split, then the coolant will not be circulating under sufficient pressure to run through the heater matrix. Probably not a good idea to drive the car at all if it's not cooling properly and is losing coolant or the engine will overheat. Open the bonnet and see for yourself. It is situated among the higher components.
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