If you want to get car loan at the fairest rate possible then you will need to have a credit check done.
WARNING: If you read this website, your chances of getting car finance with bad credit will dramatically improve.
Often a financier will be lending you thousands of dollars and they need to understand the best they can who they are lending to. It's not just a credit check they will want to see from you. The lender will also want your drivers licence, payslips and often 90 days worth of bank statements. They will even conduct rental and employment references.
However, if you are worried about putting a "hit" on your credit file, then don't be. Anyone you work with, whether it be a broker or direct with a lender will be able to give you a good understanding from asking you a dozen or so questions on your likelihood of being approved. If you feel you have a good chance of being approved, then go ahead, let them check your credit file.
Would you lend money to somebody you didn't know? Of course you wouldn't and its no different for lenders. But, they do want to lend money. As long as your credit file isn't too bad and the general overview of your profile works for them, you will get a car loan.
Understand your chance of being approved before doing a credit check. Make sure before you run the credit report that you have the capacity to repay any loan. If someone offers you a loan with no credit check, proceed with extreme caution.