How about a 20 minute job that has taken two weeks (thankfully not full time)! The new BMW thermostat seems a little too long, to put it in place the spring needs to be compressed a little,which makes the assembly more challenging. The new t-stat is safe on my workbench now. I put the housing together probably a dozen times, with and without gaskets, various combinations of sealants, etc. Refilled and drip, drip, drip! I flattened the removable housing by sanding (Thanks BillR) and it wasn't really too bad, I checked the block housing with a straightedge and it looked flat. What I think the trouble was... not thouroughly cleaning and removing all traces of glycol on the block side. It seems this must have created the pathway for the leak, even with the housing tightened pretty well. Will I have any troble running the car w/o the T-stat? I'm guessing the water temp is about 130F as I can hold my hand on the raditor hose etc. Thanks for the help.. Just think of my pleas for help when I tackle something a little more complex!