UK Car Repair: cooling system pressurising, diesel laguna, water pipes

Question
I wrote to you earlier re my renault laguna heater not working and all the water pipes seem hard  tried to open the link but unable to the car is a 1996 diesel laguna

Answer
Hello I am still a little confused. Is your concern the potential overheating or the heater?  If the car is heating so much that it pressurises the hoses, yet the heater doesn't work, I would suspect the thermostat,if it didn't open these would be two of the results.