Picture of Replace auxiliary thermostat in BMW E34
Located in the air intake filter box is a auxiliary thermostat. Made out of plastic, so over time (decades) it becomes brittle and it's two hose fittings tend to crack at the base and brake off. Either scenario is highly undesirable, as it sure will cause leak in the cooling system with following overheating, etc.

I do all my car repair at TechShop, Menlo Park (http://www.techshop.ws/), conveniently located just a few blocks from my house. They have a nice car port with plenty of heavy duty car tools.

Step 1: Getting the parts

Picture of Getting the parts
When initially confronted with the problem of getting the right part, you get mad at the fact, that this little part is sold by BMW dealerships for over a hundred bucks. You'll find plenty of forum posts on the web, where people just recommend bypassing the thermostat all together. Instead of doing that, I'd recommend getting it from an OEM supplier, same exact part made by Wahler for BMW production line sold at around $50 at PelicanParts.com.
tlynch12 years ago
you cant cap those off close to the motor ?
Doctor Jazz (author)  tlynch14 months ago

I've seen people do that, but never felt good about making "shortcut" modifications to the engine. I guess, german engineers put it there for purpose.