No matter what type of car you drive, there are going to be certain issues that arise with it. Even if you maintain your car well, change the oil regularly, have it inspected consistently, and never push the engine anywhere near its limits, there will be occasional issues to deal with. That’s true even with BMWs.
Mostly during the summer months in Toronto, one common issue that drivers notice is water dribbling from under the car. Most of the time the water is pooling and then draining out from under the engine, though at times there may be water near the exhaust as well.
This is most likely due to the air conditioning system of the car. One of the byproducts of running an air conditioning system, or compressor, is water. If you have any type of air conditioning system in your home, you will notice a drain line (if it’s a central air system) or that the window units drip water outside when they are operating.
During the summer, more drivers are cruising down the road with their air conditioners running, which creates more water in the system. When the car is idling while parked in order for someone inside to remain cool with the air conditioning running, then the pool of water forming under the car will expand and eventually it can stream out from under the car.
When the BMW owner gets back to his or her vehicle and notices water coming from underneath, it can create a small panic. On blacktop or dark pavement, it is a bit difficult to tell whether it’s oil or water. The best way to inspect it is to place your finger in the fluid and draw it back. If it’s clear and odorless, then it’s likely water from the air conditioning system. If it’s black, it’s more likely oil.
On certain occasions, though, the water could come from a leaky hose of water pump, which could indicate a more serious problem. If it’s a significant amount of water and the car was running in place for a while in the heat, then you can relax; it’s just the AC running.