Is suinga manufacturer of a tire cleanerworth the trouble?

Your boyfriend could sue the manufacturer of the tire cleaner and also the seller (store where the product was purchased).  Both the manufacturer and seller would be named in the same lawsuit.  The lawsuit would be for negligence and strict liability.  Negligence and strict liability would be separate causes of action (claims) in the lawsuit.

Negligence is based on the failure to exercise due care (that degree of care in this case that a reasonable manufacturer would have exercised under the same or similar circumstances) to prevent foreseeable harm.  In order to prove negligence, it will be necessary to prove duty (mentioned above) breach, actual cause and proximate cause. 

Breach of the duty of care occurred if the product is defective.  This could be either a design defect or a manufacturing defect.  Actual cause means but for the application of the tire cleaner, would the tires have spun out resulting in the damage to the car?  If the answer is no, actual cause has been established.  Proximate cause means were there any unforeseeable intervening events that would relieve the manufacturer of liability?  If the answer is no, proximate cause has been established and the manufacturer is liable for negligence.

Strict liability means that the manufacturer is liable even if due care had been exercised.  In product liability cases, the seller of the product is liable under strict liability even if the seller was unaware that the product was defective and /or could not have discovered that the product was defective.

Damages (the amount your boyfriend seeks to recover in the lawsuit) would be the cost of repairs to the car.  The most expensive place to have the car repaired cannot be selected as the repair shop because of the duty to mitigate (minimize) damages.  Selecting a repair shop whose charges are comparable to other repair shops in the area would be acceptable and would mitigate damages.  If a very expensive repair shop is selected to do the repairs, failure to mitigate damages will result in the damages being reduced accordingly.  Damages could be recovered from both the manufacturer and seller of the tire cleaner.

The manufacturer and seller of the tire cleaner could assert the defense of assumption of the risk which means one recognized and understood the danger and voluntarily chose to encounter it.  An example would be if there was a warning on the tire cleaner as to how much to use and that warning was disregarded or if there was a warning about waiting a certain period of time after applying the tire cleaner before driving the car and that warning was ignored.  These are just examples which may or may not be applicable in the case.  Assumption of the risk is a defense to negligence and strict liability.  Assumption of the risk would be applicable if the tire cleaner was used in a way contrary to the way it was supposed to be used.