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