Liquefaction of auto crusher residue (ACR) in hot motor oil with product oils recycling was investigated. Approximately 86% of oils, 10% of noncondensible gases and 4% of metal-rich residues were recovered from liquefaction of ACR at 643 K. The cuts of the product light oil weighted into boiling fraction are primarily naphtha (30.2%) and gas oil (68.6%). The product heavy oils recovered from liquefaction of ACR contain noticeable amounts of gas oil (95.4%). Proton NMR and FTIR data reveal that the condensation reaction may be involved in the ACR liquefaction process. However, the undesired condensation reaction is decreased significantly in the liquefaction of ACR effected by Fe2O3, FeO or CaO.