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