Beloved by car enthusiasts but not necessarily mechanics, BMWs raise some real questions about the legend of German reliability.
Running hot is a problem cars from all marques face, and BMW is no different. If you thought that trim panel was expensive, you’ll split a wig when you see the price of new motor components for your beamer. So if your car is running hot, be quick about identifying the issue and implementing a fix. It could make a five-figure difference in your bank account. Here’s what to do.
Know How to Recognize Overheating
Modern BMW engines are water-cooled and do a pretty good job of staying at operating temperature — unless something goes wrong or you’re running the car very hard. Depending on how new your vehicle is, a gauge will indicate the head and oil temperatures of your engine in the central cluster, and you might have a digital readout that displays an error code if it gets too hot. In analog gauge clusters, the needle should never touch go past the halfway mark on the dial.
If you see this happening, don’t continue driving the car because you can do severe damage to the engine. Pull over and call a tow truck. You can repair the issue once a mechanic has had a chance to take a look at things, which may cost a few hundred dollars, but it will save you the price of replacing an engine.
Fixing an Overheating Engine
Now that you know that your engine is overheating, you need to repair it. If the car overheats during regular use, your set of suspects will include your electric fan, water pump and thermostat. You should be able to observe your fan switching on and off. If you can’t, look at the thermostat and if that doesn’t do it, check your fan and fusebox.
If the car overheats at idle, you’re probably dealing with a busted water pump. Make sure you have clean, high-performance oil in the car, as allowing it to degrade or running a cheap motor oil can increase your chances of heat soak.
All these are relatively cheap to replace, and some BMW models are known for having less-than-stellar fan or water pump performance. Your mechanic will know just what to do. If the car has been overheating for some time, you’ll want to check the expansion tank to see if it has become weak.
For drivers who frequently track their cars or engage in spirited driving that causes heat soak, something more serious is needed. Consider upgrading your car’s plastic cooling system to a metal one with a larger fan and radiator. Change your factory oil for something with a higher boiling point, like a full synthetic. This will ensure fewer metal shavings enter your motor and provide better performance in the long run, as well as defend against heat soak during track days. The truly extreme can look for ventilated bodywork, a higher-volume intercooler and turbo plumbing.
Beamers have their fair share of unique issues, but overheating isn’t one of them. These problems have been faced time and time again by the automotive community, and as long as you get to them quickly, they’ll be cheap and easy to fix. Don’t wait until your head gasket breaks. Pay for the fix now, and you’ll be glad your car isn’t down for the count tomorrow.