Surface air-cooled oil coolers (SACOC) are one of the reference technologies adopted in modern turbofan engines to meet the lubricant-cooling requirements. Installed in the by-pass duct, the SACOC are usually composed of a series of staggered fins dissipating the heat load of the engine oil through forced convection with the by-pass flow. Due to the pressure drop generated by the SACOC, which reduces the propulsive thrust of the engine, the performances of the heat exchanger need to be carefully analyzed. Experimentally, several studies have been carried out in wind tunnel test rigs, yet real engine flow conditions, which have a strong influence on the behavior of the SACOC, are arduous to reproduce. The objective of this work is to identify the most relevant integration effects on a finned surface heat exchanger as well as to understand how these effects should be properly replicated in experiments. To do so, conjugate heat transfer simulations are performed in two different configurations. In the former, the SACOC is installed on the outer fixed structure of a turbofan by-pass duct. In the latter configuration, the heat exchanger is mounted on a simple square wind tunnel and the inlet boundary conditions are extracted from the first simulation with different degrees of representativeness. Results obtained with the two configurations are compared, allowing us to assess the most significant sensitivities of the SACOC to engine integration effects.