A coolant fluid manifold assembly (100) for coupling to a plurality of cold plates (202, 204), wherein the manifold assembly (100) comprises a first manifold portion (102) comprising a first positioning member (122, 126), a second manifold portion (104) comprising a second positioning member (124, 128), wherein the second manifold portion (104) is configured to couple to the first manifold portion (102) and the second positioning member (124, 128) is configured to engage the first positioning member (122, 126) to correctly position the first and second manifold portions (102, 104) and hence the cold plates (202, 204) which are coupled to the manifold portions in use.