Here is the full list of all 46 Car Mechanic Simulator 2021 achievements. It takes around 120-150 hours to unlock all of the achievements on Windows.
Reach level 50
Unlock 10 parking alleys
Renovate and sell 50 cars
Paint 60 cars
Buy 25 cars from impact cars
Buy 30 cars from junkyard
Buy 30 cars from barn
Unscrew 10 000 bolts
Finish path test 25 times
Buy 5 cars from impact cars
Visit Barn 30 times
Finish all the special missions
Unlock all upgrades
Buy new car in car salon
Fix 150 body parts
Fix 50 body parts
Balance 50 tires
Finish 100 orders
Earn 2000 scrap parts
Fix 150 car parts
Reach level 3 of garage expansion
Finish lap with time under 1:50
Buy 3000 parts from main shop
Swap engine
Reach level 20
Fix 50 car parts
Sell 1000 parts from inventory
Renovate and sell 1 car
Finish test track
Paint 5 cars
Earn 50 000 CR on sell cars
Finish path test first time
Earn 5000 CR on sell cars
Earn 500 scrap parts
Buy 1 car from barn
Visit Barn first time
Finish order with money bonus
Buy 1 car from junkyard
Reach level 5
Visit a junkyard
Buy 100 parts from main shop
Pour old oil on the floor
Finish order with experience bonus
Visit Salon
Finish 1 order
Balance 5 tires