VOLVO issued a recall on the 800 SERIES model

On certrain Volvo 850, the block heater contact surface may not match correctly with the engine block as intended. In extreme circumstances the block heater may come loose from the engine block, and if being used, could possibly overheat, which may cause damage or fire if it comes in contact with other engine compartment components. Correction: Bolts used to install the heater will be secured. Where surface tolerances are inappropriate, block heater will be replaced with a heater of modified design.