We have a 2001 PT Cruiser that regurgitates P/S fluid through the reservoir upon start up in cold weather. Does not do this in warm weather. Pump has been replaced, been to dealer and private shops. Problem has been around about 5 years with varying intensity. No solution found. Most recent recommendation is to replace steering rack, thinking air is taken into system via rack when some component is cold (contracted), then fluid settles down when engine warmed and mystery part expanded by heat. Anyone worked with anything like this? Thanks.