BMW: Leaked all Eng oil in 5 min...., blown head gasket, coolant leak

Question
Hello Josh ..first i will like to thank you about the time you will take to read this...
I have a 89 525i. 5 speed
I was driving in highway and checked my temperature gauge it was goin up to the red zone i pulled over i see that i had a coolant leak and i fix the problem.(the problem was the Waterpump) bearing was gone and the coolant leaked from the pump.Now, after i changed the waterpump the Temp Gauge its always in the cold side..and the heater blows only cold no HOt.....
I wasn't conserned about that but i was worried that since my car was overheated my gaskets are not good anymore.....well guess what

I went in highway again and about 5 min later i see the temp gauge going up above Normal Temperature and pulled aside. this time I see an oil leak.. I check the coolant..the coolant its fine , the oil its below the minimum sign...
I would like you to help me at first ..why i wasnt' getting my heater to blow hot air and why my temp always at cold...and where do you think  all that oil leaked so fast...please help thank you agian..  

Answer
Joseph,
 Sounds like the engine may have ran hot.  When this happens it can warp engine components, and alter the sealing abilities of the gaskets.  Most common is the "blown head gasket", it allows oil to leak into many places.

 When you changed the water pump, did you bleed the air out of the system?  If you didn't this will allow air to stay in the system, and any place air is sitting, coolant isn't touching..... and you get hot spots.

 You should have a phillip's head screw beside your coolant cap.  While the engine is running you should open this cap (make sure it's not running hot) and air bubbles will pop up.  Make sure you have your heat WIDE OPEN as to let coolant circulate through the heater core inside the car as well.  You can idle the engine up to ~2k rpm while you are bleeding the system, and it will help remove the bubbles.

 As far as the oil leak, I have no clue.  That's something that YOU are going to have to scout out for yourself.  You said you saw a leak, so trace it back to where it's coming from.  Make sure to keep oil in the engine.  If it's POURING out of the engine, I probably wouldnt' drive it until I found the leak.  There are some leak detecting tools that are helpful sometimes.  UV dye is the best.  You can go to a local parts store, and pick up a UV light and Dye kit for probably $20.00.  Pour the dye into the engine oil, dim the lights and shine the UV flashlight onto the engine.  anywhere the dye/oil is leaking, will glow bright orange.

 Hope this helps,
 Josh