Q: Coolant finishes 3-4days

Hello. This can be caused by a number of things such as low coolant levels, a faulty thermostat, or a failing coolant fan switch. The fact that you are losing water every 3-4 days without leaks, this would suggest the engine is burning the coolant. You may very well have a blown head gasket. When this happens, the coolant leaks into the cylinder and is burnt with the fuel charge. This happens when the cylinder head gasket has failed typically due to a pre-existing overheating problem. I would suggest checking your oil to see if you find traces of water in it. Also you may want to check the coolant shortly after refilling it after the car has been run. If there are traces of oil in the coolant, then this may confirm that you have a blown head gasket. I would suggest having an expert from YourMechanic come to your home to diagnose your coolant leak](https://www.yourmechanic.com/services/coolant-is-leaking-inspection) and make the necessary repairs.