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