Coasting has no real affect on the internal mechanics of your car. However, it does lead to the overuse of one clutch component in particular for manual cars: the throw out bearing. The throw out bearing is the part of the clutch system that disengages the engine while the clutch pedal is pressed.
Coast in neutral to save fuel
Not only that, it's also unsafe as you don't have full control over the car when it's in neutral. It means you can't suddenly accelerate out of a sticky situation and you lose engine braking, running the risk of overheating the brakes when going downhill.
The basic definition of coasting is driving with either your clutch fully down or your vehicle in neutral (not in gear), it happens when you put the clutch down unnecessarily or too early.
Coasting has no real affect on the internal mechanics of your car. However, it does lead to the overuse of one clutch component in particular for manual cars: the throw out bearing. The throw out bearing is the part of the clutch system that disengages the engine while the clutch pedal is pressed.
It's dangerous & puts extra wear on your brakes
The main problem with coasting, other than that it increases fuel consumption, is that the car enters a state of free momentum – which means that it can easily get away from itself when going downhill.
While braking, you should always depress the clutch.
This is one of the most common scenarios wherein people do apply the brakes but forget to disengage the clutch in-turn stalling the car. Well, stalling the car especially with transmission load will take a serious toll on your vehicle's gearbox assembly.
You might want to wait until you get to 35-40MPH before downshifting from sixth to fourth to third – using the brake, clutch and accelerator pedals properly. Do be careful if you slip into a much lower gear on the downshift. You might end up to over revving the engine, which could cause problems down the road.
The clutch is subjected to constant friction, so it is unsurprising that it will wear out eventually. You may find that your clutch lasts 10,000 miles before you need to get a new one or you could drive 150,000 before it gives up.
The most wear and tear done to a clutch is when the pedal is only half depressed. Do use the brake to hold yourself stationary on a hill, rather than the clutch. Do take off in first gear, rather than third. As a convenience, too many people will cut the engine in third and take off the following day the same.
The average lifespan of a clutch is anywhere between 20,000 to 150,000 miles. Luckily, your clutch will likely give you ample notice that something is going wrong. Don't get left at the side of the road with a vehicle that won't shift into gear.
The trick is to let the clutch out to the engagement point quickly and then more slowly from there. The only way you can know where this engagement point is, is by getting a feel for the car.
As others have said, don't coast in gear with the clutch in. This will wear the release bearing unnecessarily. As for coasting in neutral, you won't have any engine braking. This will result in the vehicle wanting to pick up speed much quicker than with the transmission in gear and the clutch out.
How to avoid riding the clutch. If you're sitting too close to the pedals, you might find yourself resting your foot on the clutch for comfort's sake. Try moving your seat further back to give your foot a little more space. This should help you to avoid resting it on the clutch pedal.
What's the secret to changing down gear smoothly? Maintain light pressure on the accelerator pedal as you press the clutch down, change gear and then clutch up gently (or the car will jerk). Using the accelerator will raise your engine speed to match your road speed, ultimately giving you a jerk free gear change.
Releasing the clutch too soon
Most of the professional drivers learn the art of operating the clutch perfectly early on in their lives. Many people who drive cars daily release the clutch too soon which makes the car jerk, which on the other hand puts excessive pressure on the engine and the transmission.
As your speed is already less than the lowest speed of the gear, your car will struggle and stall, when you brake. To avoid this, you would first need to press the clutch so that the engine is not dependent on the transmission and then start braking.
Technically, you are putting additional wear on the throwout bearing if you do not fully release your clutch pedal and allow the clutch to fully engage the flywheel. This includes stopping at an intersection for an extended period of time.
If you're going round a corner, you will need to reduce your speed, so it's likely you'll need to change to a lower gear as well. This will give you much better control around bends in the road—something that might be familiar to you if you've driven much along country lanes.
You have less control because you can't control speed via engine braking - since the engine is not connected to the wheels. It becomes more challenging to take a safe, steady line around a corner - meaning you'll have less control if you cross the path of another road user or other hazard.
Explanation: When coasting, the engine is disconnected from the drive to the wheels. This means that the engine's resistance can't be used to help slow the vehicle, especially when travelling downhill.
Yes, coasting can be considered a major fault and could cause you to fail your driving test. Coasting occurs when you disengage the gears and allow the vehicle to roll without engine braking. This can be dangerous as it reduces the driver's ability to control the vehicle and increases the stopping distance.