Engine coolant getting low. Expansion tank replaced due to possible leak but issue not fixed.car started giving white smoke while away from home. Car stalls after jittering /shaking. took the car to garage in Manchester and guy diagnosed egr cooler need replacing. Part replaced and car started fine but after 3 hour journey back to home, noticed no coolant in the tank gain(low coolant warning when few miles away from home ⚠). After reaching home I topup with water. After few hours checked the car and coolent vanished again, even car was not started since topup. I filled the tank to max and started the car. white smoke coming again from exhaust.
Temperature never went above 90.no water on the ground. No visible leak. where is coolant going even car is idle? It's definitely not leaking outside as getting white smoke and thats alots of smoke. Smoke getting less after few minutes. I will take the car to my local garage tomorrow. Any idea what could be the cause?

 

100% sure it's not external then coolant need to be checked for co2 gases, there's a kit that you can buy that does this in the US. Not sure if they sell it around your parts. Possible head gasket or cracked head. Turbo coolant leak not likely.