My coolant reservoir has frozen solid but the hose that runs from it is fine, engine was running fine over the last week where temps have been -2 highest. Only noticed when amber light appeared on dashboard, is this likely to have caused any permanent damage? We have a clio

Angela Atherton, December 2010

it happened to me last year,when i filled my car with normal water and brok my starter motor belt when tried to start engine... recovery man towed it to home and suggested to let it un-freez and drain, then get checked if frozen water damaged the engine/radiator etc (as water get expand at freezing point)....
luckily it was only the matter of changing "core plug" a total £4 job to get it replace by a local mobile mechanic.
and filled with proper anti-freez, fully concentrated.
core plug is the light weight metal cap somewhere undernith car, which gets crack (avoiding damaging engine and other expensive equipment) and gives space to water to get expand.

Imran, December 2010

on no account start this motor until it is thawed out thoroughly,drain coolant and refill with 50/50 a/freeze mix and begin to pray you haven`t knackered your engine

cdc, December 2010