It's a good idea, but not necessary. I always do, but know lots of people who don't.
Yes, if you don't your car can wear out faster so you have to buy a new car more often.
A good practice is to let your engine idle for a few minutes after starting so the oil pressure can build and lube all the internal parts of the engine. A vehicle with turbo should be idled before shutting off to let the turbo cool down.
after shutting off the engine engauge the emergency brake pedal before restarting your engine.it should interrupt the lights .i know it does with mine.
Where is the best place to park your ATV after shutting off the engine
If it's carburetor engine, the throttle may be shutting completely.
The 1998 Buick Riviera air conditioner compressor is located in the engine compartment. The air conditioner compressor will be on the left-hand side of the engine.
Using a Diesel fuel conditioner would be good for your engine and would not be bad at all.
Usually caused by a timing problem.
The 2004 Toyota Tacoma air conditioner compressor can be found on top of the engine. The air conditioner compressor will be on the left-hand side of the engine, near the front.
The air conditioner will not cool the engine. On the contrary, the a/c will put more load on the engine and make it overheat sooner. You need to pony up and get the water pump repaired before any major damage is caused by overheating.
if you mean engine fans,then a quick way to test is,if your car has air conditioner start engine and let idle turn on air conditioner and turn interior fan to high,this will,or should make your thermo or engine fan operate,if it does not you will have an electrical fault,ie fuse,fan motor ,relay,
If the engine continues to run after you have turned the key off you have what was called "Dieseling". Checking the timing and set the idle to factory specs should cure it. Shutting the engine off while stopped in drive will stop the engine for now until you get it looked at.
while driving they serve to add visibility. If they stay on after you shut off the vehicle it is so you can make it to the house and find your key to get in when its dark, they should go out in a few minutes. You can probably avoid this by shutting them off before turning off the engine