Hard to start up engine cranks over 5 to 6 times before it starting

Check that the glow plugs are working , the relay is in the e-box(big black box in the right front of engine bay)remove the glow plugs and individually test them.They should glow red after 3 seconds .

Took me a long time to sort, but in my case it was a leaking injector. See if you can get your mecanic to run a leak test. I'm sure the kit has a fancy name, but in essence, they hook up a gadget that allows fuel to pass the flow from each injector into a series of 6 side-by-side plastic tubes - then crank the engine. In my case it was clear that no. 4 injector was passing way, way too much fuel compared with the others. Changed the injector and bingo - instant starting every time.

Hope this helps

wrong battery