Do i need to pay car sales tax in California buying from a private?

Yes, but it is called as 'used tax'. "Use tax is generally imposed on the purchaser of tangible personal property that is used, consumed, or stored in this state. Sales of vehicles, vessels, and aircraft by licensed dealers are usually subject to sales tax, for which sales tax reimbursement is collected at the time of purchase. Use tax applies to the cost of vehicles, vessels, and aircraft purchased from non-dealers (for example, private parties) or from outside California for use in this state. Use tax also applies to most leases of tangible personal property. Private party sales or brokered transactions are normally subject to use tax. If the first use of the property occurs in California, use tax may apply even if the purchaser is not a resident of the state. The sales and use tax are "mutually exclusive," which means that either sales tax or use tax applies to a single transaction, but not both."