Catalyzes the hydrolysis of acyl-CoAs into free fatty acids and coenzyme A (CoASH), regulating their respective intracellular levels (PubMed:16940157). Mainly active on medium-chain acyl-CoAs (PubMed:15007068). Seems to be involved in intraperoxisomal regulation of acyl-CoA levels, but not CoASH levels (PubMed:15007068). May have a function in termination of beta-oxidation of fatty acids (PubMed:15007068). H2O + hexadecanoyl-CoA = CoA + H(+) + hexadecanoate decanoyl-CoA + H2O = CoA + decanoate + H(+) H2O + octanoyl-CoA = CoA + H(+) + octanoate dodecanoyl-CoA + H2O = CoA + dodecanoate + H(+) H2O + tetradecanoyl-CoA = CoA + H(+) + tetradecanoate H2O + octadecanoyl-CoA = CoA + H(+) + octadecanoate eicosanoyl-CoA + H2O = CoA + eicosanoate + H(+) (9Z)-octadecenoyl-CoA + H2O = (9Z)-octadecenoate + CoA + H(+) (9Z,12Z)-octadecadienoyl-CoA + H2O = (9Z,12Z)-octadecadienoate + CoA + H(+) (5Z,8Z,11Z,14Z)-eicosatetraenoyl-CoA + H2O = (5Z,8Z,11Z,14Z)-eicosatetraenoate + CoA + H(+) (9Z)-hexadecenoyl-CoA + H2O = (9Z)-hexadecenoate + CoA + H(+) Lipid metabolism; fatty acid metabolism. Highly expressed in spleen, brain, testis and proximal and distal intestine; expressed at low level in the liver. In the liver and kidney, by peroxisome proliferator, via the peroxisome proliferator-activated receptors (PPARs) and by fasting. Belongs to the C/M/P thioester hydrolase family.