BMW Repair: 97 328ic overheating, radiator tank, upper radiator hose

Question
recently bought car and drove for 2 weeks w/o any problem--did notice a slight ballbearing type sound but did not think much of it.  got home one evening and noticed uppper radiator hose was off.  seemed weird but replaced/tightened.  since then been overheating quickly (1-2 miles).  have replaced thermostat and then water pump (noticed ballbearing sound had stopped so figured that pump had gone bad).   upper radiator hose is hot and pressurized but lower hose is cool to the touch.  also no heat.   i am stumped and wife is not happy because this is her car.  don't mind taking to a mechanic but it just seems like the problem should be solveable at home.  please help.

Answer
We can start with the easy, or start with the worst-case-scenario.....let's start with the easy.

BMW's are difficult to "burp":  You need to be sure to get all the air out of the system.  There is a vent plug by the radiator tank cap.  It needs to be loosened to let the air bleed out.  Check www.roadfly.com, searching the e36 board for "bleeding" to find more details on how to do it.

If that's not it......it may be head gasket. These are high performance aluminium engines, and they don't like being overheated.  If the burping doesn't work, my next stop would be to get an "exhaust gases in the coolant" test.  Should be able to get one from a Firestone (or similar) for about $50.

(Hope you treated your wife well for Valentine's day!  Damaging her BMW ain't a good way to score points!)

Let me know what you find.  (And if it winds up being a head gasket, let me know where you live)