I had to throw a bit of money down to keep the E90 running great for years to come. A common problem on them is for the water pump (which is electric) to begin slowing down over time. BMW upgraded the units after seeing the first few years of E90’s were having issues with there pumps. I figured it was pretty important to do this before it gets real hot again this summer. I plan on making plenty of trips so it’s important for me to have my mind at ease while cruising 300 miles out to Vegas in 105 degree heat.