1. You probably ended up causing a number of skids on the roads you drove and poluted the f**k out of the environment.
2. You indefinately caused some damage to your engine... This BMW had oil leak and drained a lot of oil, they replaced the engine cos he f**ked it up.
All for a lousy oil temp gauge?
How ironic, you didnt even have any bloody oil to measure LOL
Sorry man but if you wonna be a bit of a DIY know it all and whack any shit into your car without properly checking, double checking for leaks etc, you should cop it.