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BMW Repairs: Engine Cooling System Issues

BMW Repairs pompano beach

BMW repairs are one of our favorite subjects here at Foreign Affairs Motorwerks. The German marque takes such an interesting approach to engineering that it continues to amaze us. They haven’t done a SAAB yet by combining the water pump and alternator although they got close with oil running through the alternator bracket on some of their models.

Today we are going to take a look at common cooling issues that they experience. To do this we are going to break down a cooling system and discuss each component separately.

So, let’s dive in.

1. Water Pump

This is one of the most important components in your BMW. It is responsible for pumping the coolant through the entire system. In older models it was driven off the fan belt, but in modern times it is driven via the cam belt or timing chain. Even if you run high grade coolant, eventually the seals on the bearings in the pump wear out and it will start to weep. A common BMW repair is a cambelt replacement, and we recommend that you simply replace the water pump at the same time. Alternatively, you can do it every alternate cambelt replacement as this will ensure that the pump never fails.

2. Radiator

Basically, a massive heat exchanger the radiator’s job is to get rid of the engine heat to the atmosphere. Technically there are two radiators in your auto. One is for the heater (small and usually mounted inside the cabin) while the other is the main one under the hood.

The single biggest problem with radiators is leakage. So, if you notice water dripping from the front of your auto (and the AC is off) or if your hot air in the winter smells sweet, chances are good you’ve got a dodgy radiator. It used to be standard practice to repair radiators, but these days they are simply replaced.

Another common BMW issue is a blocked radiator. If the Beemer runs slightly hot (but doesn’t overheat) get your radiator tested.

3. Fan

Without air flowing through it, a radiator is useless. So, we add a fan. BMW use two types of fans, depending on model. Belt driven fans are connected via a viscous coupling or clutch. Similar to the way old GM transmissions used to work, as the engine temperature increases, so the clutch limits slip and the fan turns faster. Also, just like GM transmissions, these often go out. This is easily noticed by the engine temperature increasing dramatically under load. Alternatively, if you peek under the hood when the motor is hot, the fan should be spinning much slower than the engine.

The other type of fan is electric which is controlled via the engine computer. Very little can go wrong with this fan and if it fails to switch on, the fault is most likely the fan control switch or block temperature sensor.

4. Hoses and Coolant

This is one of the easy BMW repairs. Hoses can simply be eyeballed for visible leaks, and you should always run a high-grade coolant as specified by BMW. Modern coolant has a long service life, and you should only need to replace it once every four years. BMW requires their cooling system to be bled in, so make sure that when it is replaced, the system is bled correctly, otherwise you’ll end up with a very expensive repair called a head gasket replacement.

5. Thermostat

Last but not least we get to the thermostat. This is basically the valve that regulates water flow through the system, again dependent on engine temperature. The hotter the engine gets, the wider it will open allowing more coolant to flow. Stuck thermostats happen; either your BMW will straight up overheat, or you’ll notice it getting too hot in town and overly cool on the highway.

BMW Repairs in Pompano Beach

By now you should have a good idea of how your BMW cooling system hangs together. However, if you haven’t had your BMW serviced or have an issue that we haven’t covered why not come and visit your favorite auto mechanics; Foreign Affairs Motorwerks? Call us today at (954) 746-0488!

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