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