Has acyl-CoA thioesterase activity towards long-chain (C16 and C18) fatty acyl-CoA substrates, with a preference for linoleoyl-CoA and other unsaturated long-chain fatty acid-CoA esters (PubMed:22586271). Plays an important role in mitochondrial fatty acid metabolism, and in remodeling of the mitochondrial lipid cardiolipin (PubMed:22586271). Required for normal mitochondrial function (PubMed:22586271). . This is the function of Ensembl gene identifier ENSG00000196407 (THEM5, thioesterase superfamily member 5).