Major service is normally done when the car mileage hits somewhere between 15000-20000 kilometres. This type of service involves the checking and replacement of serviceable parts that are critical in the operation of your car. The engine section; filters, spark plugs and lube has to be in good condition.
On the drive train side, the clutch/torque converter, brakes, driveshaft, differential unit and suspension bits like links are checked and replaced depending on the level of wear and tear. Based on the schedule designed by the vehicle manufacturer, the following critical components must be looked at during your cars major service:
1. Engine oil
Your old, dirty oil which has since turned black, is replaced with clean oil. This makes your engine run more efficiently and smoothly.
2. Filters
The oil, air, fuel and pollen filters are all replaced. This makes your car run more effectively.
3. Spark plugs 
Your car’s spark plugs that are used in the combustion process are replaced to maximize your vehicle performance and enhance fuel economy.
4. Brakes
Your brakes are inspected for leaks, wear and tear. If they are in good condition, they are cleaned using o sandpaper and adjusted accordingly. If they are damaged, they are replaced.
5. Fluid change
The transmission, clutch, brake, power steering and coolant fluids are all flushed and replaced. This ensures that the systems utilizing these fluids run perfectly thus increasing the efficiency of your car.
6. Road test
All major car services include a road test. The purpose of this is to pick up any problems that can’t be detected easily by eye inspection. Problems detected during the road test have to be fixed instantly. The road test ensures that parts like the suspension links are secured and fit perfectly.
7. Safety inspection
A full safety inspection is performed during a major service. This entails brake adjustment, steering angle position, wheel alignment, wheel balancing and radiator pressure check.
8. Battery test
This is done to confirm that your battery is charging properly and isn’t leaking battery acid. If the battery acid levels are low, di-ionized water is used to bring the levels back up to their required position. Doing this prevents you from having to change your battery pack too soon.
9. Additional checks
It is also necessary that the gearbox, transfer case, the wiper blades, all of your bulbs and diff oil are all checked.
Summary
Major service is very important as it ensures your car lives long. Taking care of your car is important as it helps to maintain its resale value. Always use genuine replacement parts and service your car at a reputable dealer who will care for your car and keep service records for future reference.