Please help, 1998 318I E36 won't start on hot weather

[samsungd838]

I live in central west of NSW.Australia
The weather has been rediculous hot.
When i start the car in the morning it was perfectly fine.
But when it gets hot (under the sun) i have to hold the key on the ignition for 1-2 seconds to get it start, after it start its not.
Now it getting worse, sometimes when i turn the key, all the instrument light came on but the motor won't turn at all , not even a click!

Wait till sunset and car cools down, go back to start the car, it starts straight away, no sign of low battery or anything.

No i am trying to put sun shade in front of the windscreen when park under the sun, it helps little bit.

I am thinking, could it because the heat tricks the immobilizer to keep the car from starting? When it not starts up and i pull out the key , the key is really hot, but the dash is hot as well, because we got arround 40 degrees!


Any one have any idea would be appreciate.

[VMZ]

Is it a manual? I've heard of clutch stops swelling just enough to not let the car start.
You could do a visor test. Fold your visor down and slide the think open so the light us on. Turn the key and see if the light dims.

There's so many reasons a car won't start when hot. It's going to be hard to diagnose over the net without more information.