We report on magnetization, magnetostriction, and magnetocaloric-effect measurements of polycrystalline LaFe11.74Co0.13Si1.13 and LaFe11.21Co0.65Si1.11 performed in both pulsed and static magnetic fields. Although the two compounds behave rather differently at low fields (∼5 T), they show quite similar values of the magnetocaloric effect, namely a temperature increases of about 20 K at high fields (50-60 T). The magnetostriction and magnetization also reach very similar values here. We are able to quantify the magnetoelastic coupling and, based on that, apply the Bean-Rodbell criterion distinguishing first- and second-order transitions.