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