JLR and West Midlands police are probing the theft of a reported £3M of engines from its power train operations near Solihull.
Police have been told a lorry tractor-unit visited the Damson site twice over 31 January and 1 February and drove away two trailers loaded with new engines.
The trailers have since been found empty and been examined by forensics officers for traces of operators or other evidence.
A JLR statement merely confirms the theft but does not confirm the value.