Engen Refinery plant is part of the Engen Petroleum Limited, with operations in Southern Africa. The plant is situated in KwaZulu-Natal province of South Africa and it operates 24 hours a day, every day, including weekends. Although Engen operates 24 hours 7 days a week, the plant has to be shut down occasionally for maintenance. These shutdown periods are also used as an opportunity to implement most projects, especially those that could not be implemented during the normal run of the plant. In order to ensure that the plant operations are not interrupted, it is preferable to work on the equipment while the plant is not operational. The shutdown periods are very limited in time, so it is of utmost importance to complete tasks within the given turnaround period in order to get the plant back on line in time to deliver products as scheduled to customers. The main objective of this study is to explore the causes and consequences of delays in project execution and their impact on the success of the project. The study identified poor communication, repetition of tasks, resource allocation, scope change, procurement process management, inadequate planning and poor budget estimates as major contributors to delays and cost escalation during project execution. It is recommended that Engen Refinery put some means together to improve the above-mentioned issues