2002 Chevy Caprice multiple problems need your attention

1. Loud rattling type noise " qirrh qirrh qirrh qirrh" appear on speeds above 120kmph after 5-10 minutes driving. The noise settles down in the city with slow driving after some time.
2. Morning first start crank sound is very loud and settles in about a minute.
3. Oil seep at the under engine area all over, but no dripping leak. Oil level drops gradually when I check the engine oil level by inspecting the inserted rod after opening the hood.
4. Car starts choking when the fuel level drops below the 3rd quarter on the gauge.
5. Heating level indicator gauge moves up to mid level, fan starts up and brings it down to the normal resting level. It happens even in winters. Sometimes coolant also leaks out of somewhere and is seen on the under road specially when air con is turned off and the car is parked.
6. Oil and fuel pressure sensor indicator turns on on every fuel refill and on many speed ramps.

thank you for all the bothering.