I drive the 2001 s-type 3litre v6.

when i start the car is the morning,, its normal temperature inside. ( no AC )

However, after driving for a while ,when the engine starts to heat up. ( against normal engine temperature ) the heat sips in from under the dash board to the driver & co-drivers legs. The heats increases as the car is driven for longer. ( even when windows are down ).

what could be causing this ?

as a side note: ( another issue )
Been told by mechanic that power steering pressure switch was causing oil leak and needs to be replaced. would this cause the a fore mentioned problem ?