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