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