White smoke from exhaust

After about ten minutes of driving, I am getting a lot of white smoke from the exhaust. If I clutch and turn off the key/engine and turn it back on immediately (I know not the safest) the smoke stools for about ten minutes but comes back and I repeat the process. The problem can go away for weeks but returns again for weeks. I have had all sorts of diagnostics done and have had a few garages look at it to no avail. It is our second car and I am going to get rid of it so I was not willing to invest too much in the problem. It is mostly curiosity at this stage. Anybody have any ideas? ☺️