Originally Posted by Zaggeron

I believe you have a case, but not necessarily against Nissan. You may be able to show that not enough oil was put in at your last oil change. Based on the various comments from folks here who know what they are talking about, it is highly unlikely that your engine lost 5 full quarts in 3 months with no outward signs. The likely culprit is too little oil was put in after the change. If this is the case, your beef is with your oil change place.