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