Recently, there has been a push within engineering curricula to adopt more learner-centered pedagogies, such as case-based instruction. Case-based instruction has been hypothesized to make the curriculum more relevant and motivating for students by pushing them to integrate the concepts they have learned with other experiences. The current study examined the influence of case-based instruction when compared to traditional lecture-based instruction within a mechanical engineering course on student performance in terms of learning, conceptual understanding, and student perceptions towards the two approaches. Seventy students from one systems course in a mechanical engineering program participated in this study. The study utilized within subjects posttest only experimental research design to assess student learning and engagement from cases. Participants completed posttests and a survey. We found that students' conceptual understanding was significantly higher when learning from case-based instruction as compared to traditional lecture. Additionally, the survey results exhibited that cases allowed for significantly more engagement and connections to the real world. However, students reported that cases were not better in improving their learning. Given limited research on the effectiveness of case-based instruction in engineering, this study provides empirical support for the use of cases in engineering. We also argue that student perceptions are not accurate predictors for their actual learning outcomes. Implications for engineering educators and directions for future research are offered.