I am in need of a new engine due to Valvoline not tightening the oil drain cap after a routine oil change. Can I sue them?

I am now in need of an entirely new engine (totaling approx $2,500) due to my oil drain cap/plug falling off while on driving on the freeway, and all of my oil drained out, killing my engine. I filed a claim with Valvoline, who referred me to their Insurance company. After FOUR WEEKS of them investigating (mind you, they would've never gotten back to me if I hadn't actively called them every other day asking for updates), they are claiming they are not liable for the drain cap coming loose and my oil draining. Bottom line, they will not pay for a new engine. Their reasoning is that I was 150 miles past the recommended 3k mile change, and if I would've brought it in on time, this would've never happened. What are my options? Am I able to sue?