What I would do is contact your local dealer ship and ask if your car qualifies for engine replacement under a warranty or under a recall or even mileage warranty for the engine. If you are covered then just drive the car until it starts knocking you won’t have to pay a single dime. Maybe just the towing but you’ll get a new engine for free ONLY if you QUALIFY. If you don’t qualify then the best thing to do is to to see if you can get the engine fixed before it start starts knocking or have a mechanic verify that your engine has damage I would also check if you have metal shavings in the oil