Will I win?

My brother borrowed my car and destroyed the engine by letting the transmission run dry. I told him to pour transmission additive into the transmission at least once a week. He obviously didnt do it. When the car broke he offered to pay. This was 7 months ago and now he is refusing to pay. I threatened to sue but my dad as well as my brother both say I will not win. What is your take.

Note: I live in california. Car is worth no more than 1900 in excellent running condition

You won't win. You took the risk of loaning it to him, it's on your head. Granted it was his responsibility to take care of the car, but being brothers, you should have forseen his irresponsibility and not loaned him the car in the first place. The jury will take no pity on you.

Actually, you could win under Embailment. This means that if someone borrows your property, they have an obligation to return that property in the same condition, that it was lent, absent normal wear and tear. You set a condition that your brother put in transmission additive in your car once a week, when you loaned the car to him. If he didn't meet this condition, he may be liable for damages. However, you would have to prove that he did not meet this condition. You would also have the burden of proof that the transmission was in good condition when he borrowed your car. If it was necessary to add a transmission additive every week, this does not suggest that the car was in very good condition when he borrowed it, as this may be the end result of normal wear and tear.