You should always bleed the cooling system after draining it or opening it somewhere other than the expansion tank. By bleeding the system, you can make sure there are no air pockets and the coolant can function as it should. It’s an electric pump, thus the bleeding procedure requires a powerful battery. We finished the procedure without a battery charger, despite the BMW repair manual’s recommendation.
The self-bleeding technique should be started by:
The bleeding can then be started by depressing the accelerator pedal for roughly 10 seconds. When you hear the coolant within the engine and radiator moving, you’ll know the procedure has started. Once it has begun, let the car alone for 8 to 10 minutes. After that, the procedure will be finished, and your cooling system will be totally bled and ready for use.
Authored by:
owner of a 1973 Porsche 914 and a 1998 Impreza 2.5RS with a flat-six engine swap. only when opposing perspectives are horizontal.
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How to bleed a water pump that is mechanical (older BMWs)
Tools Required:
- Jack (depending on model)
- Jack postures (depending on model)
- the screwdriver
- Auto Key
How can you tell if your water pump is mechanical? A mechanical water pump is almost probably present in a BMW that was built before 2004. With the E90 in 2004, BMW started adding electric water pumps on the 3 Series. The E46, E36, and E30 are belt-driven mechanical water pumps, as are all prior 3 Series models.
These older BMW models require manual bleeding. Even while it’s a fairly quick and simple process, it does require more patience and time than versions of electric water pumps that “self-bleed.” These automobiles have mechanical water pumps, thermostats, and reservoirs positioned on the radiator’s side.
**To lift the front end of these vehicles, I utilize a jack, jack stands, or ramps. Why? Because the bleed screw and radiator are now the highest points on the coolant system, this will let the air move more easily. The majority of people don’t do it, but in my experience, it’s the best approach to guarantee that all air bubbles are eliminated from the cooling system.
**This bleed method will still function flawlessly if your heater is broken. I’ve done this procedure a lot of times when someone’s a/c control module has failed. Simply omit the step requiring you to turn on the heat.
- Put the front end on ramps or jack it up. (This step is advised but not necessary.)
- Open the bleed screw, then add coolant until it reaches the fill line. Take off the fill cap.
- Set the fan speed and the heat to their highest settings.
- The engine should be started and given time to reach working temperature. Release air when it heats up by loosening the bleed screw, then tighten it again.
- Reinstall the fill cap and tighten it firmly. Press the gas pedal to increase the engine’s rotational speed to 2000–2500 RPMs. If your heat works, it should be pumping hot air at this stage at full force. You can see from this that the heater core is dripping with coolant.
- After tightening the bleed screw, setting the car down and giving it a short spin, you’re done!
What occurs if BMW fails to bleed the coolant?
My 2014 335i gt’s radiator vent line broke, leaking some coolant, therefore I had to follow the instructions for bleeding the system after adding the coolant back in.
If anyone knows why they don’t just instruct you to put the engine on and drive about to let the air out, please let me know.
I have some ideas, but I’m curious if someone here who is “in the know” could clarify this.
You can’t fully fill the system with coolant if the air hasn’t been bled out. The hoses will contain air entrapment areas. If the engine and transmission are operated, they may overheat and destroy a variety of parts, beginning with the water pump and becoming worse from there.
No, the purpose is to remove air from the system. Since the system is sealed, any trapped air will remain there unless it is purged. For this reason, the coolant must also be injected under pressure into the circuit. This Oldsmobile is not your father’s.
Oh, I understood what bleeding was and why it was necessary. I apologize if I was unclear.
My concern related to how BMW decided to handle it. My friend and I are discussing how you bleed the system on a BMW as opposed to another kind of automobile. He believes that BMW’s process is overly complex. Procedures like these don’t exist simply because they do, thus I believe there is a strong rationale for it.
So here’s my inquiry: what design issue was BMW attempting to address by developing a method for bleeding the coolant circuit while the engine is not running?
I don’t necessarily see a design issue. If you wait for the engine to reach operating temperature before the cooling system can purge trapped air, damage may occur before the air exits the system since coolant doesn’t circulate through the system completely until then. That cannot occur if the air is purged without starting the engine.
He is referring to a thermostat; once the coolant reaches the desired temperature, the thermostat opens, and the coolant circulates throughout the entire system.
Don’t forget to fully activate your heater so that the water can also pass through the heater core.
No car, not even an Oldsmobile or a Honda, can be bled by just driving it around; instead, a bleeder screw is located at the highest point of the cooling system, or the overflow/radiator cap is used.
What is the time required to bleed coolant on a BMW?
Depending on the model and approach you use, it typically takes 15 to 30 minutes. However, heating the engine and draining the coolant both take about 15-20 minutes.
Between the overflow tank and thermostat, your cooling system can leak a little. However, you must fill the coolant and drive the vehicle with the radiator cover off in order to fully bleed.
The water needs to be turned on and adjusted to run slowly. To remove the radiator from the cooling system, turn off your car.
Can a radiator be bled while it is running?
You’ll require:
- A radiator key is available from a home improvement retailer.
- To catch any water, use a cloth or rag.
- Shut off the heat. When the heating is on, you can’t bleed a radiator because it can be too hot to handle. The radiator can also start to shoot hot water.
- Turn the valve on the radiator’s top using your radiator key. As illustrated in the diagram, secure the key in the square groove at the center of the valve and turn it slowly counterclockwise. There should be a hissing noise. The air that was imprisoned is now exiting. Use a cloth to collect any spilled water.
- Once the hissing stops and only liquid is released, retighten the valve. To prevent too much water from escaping, act soon.
- Restart the heating system in your home.
- Utilize the gauge on your boiler to check the pressure. The pressure may decrease as a result of bleeding your radiators. You’ll need to top it up if the pressure is too low. Use the filling loop, a lever or tap on your boiler.
- Verify that your radiator is currently heating up appropriately. You’ve solved the issue if the radiator is now heated uniformly.
When it’s chilly, can you bleed a radiator?
Should I bleed the hot or cold radiators? Before attempting to bleed your radiators, always make sure your boiler is off and your central heating system is cold. Your radiators hold hot water when they are turned on, so bleeding them now puts you at risk of burning yourself.
What happens if a radiator is bled while the heat is on?
When the heating is on, you must not bleed radiators because the hot water may fly out of them and they may be too hot to handle. Before you start bleeding a radiator, make sure the heating is switched off. If you release air while the pump is functioning, more air will be drawn into the system from somewhere else.
Which coolant does BMW employ?
No matter what type of car you drive, whether it’s a BMW, Porsche, Mercedes Benz, Audi, Mini, or Volkswagen, your car circulates a solution of water and coolant to dissipate the heat generated within the engine and prevent it from completely melting down (one notable exception are older Porsche models that are air and oil cooled and did not use water or coolant, but instead circulated a large amount of oil to dissipate the heat).
A Spectrum of Colors
Which coolant type is best for your BMW, Porsche, Mercedes Benz, Audi, or Volkswagen out of the many available options? The answer is the kind that was initially installed in your car. Your coolant may be green, pink, blue, yellow, or even clear depending on the manufacturer. All coolants are naturally transparent, and dye is used to give them color. It has no impact on the coolant’s chemical properties that each producer adds their own colour blend. Because the water in Europe is substantially harder than the water in the United States, European manufacturers prefer coolant that is phosphate-free.
Inorganic Acid Technology (IAT), Organic Acid Technology (OAT), and Hybrid Organic Acid Technology (HOAT) are the three most common coolant types available today. A HOAT coolant is used by your BMW, Porsche, Mercedes Benz, Audi, or Volkswagen.
In order to protect aluminum surfaces, silicate is added to OAT coolants to create HOAT coolants. The cylinder heads and radiators, as well as other parts of your BMW, Mercedes Benz, Porsche, Audi, and Volkswagen engine and cooling systems, are constructed of aluminum.
Silicate and phosphate corrosion inhibitors are not used in OAT coolants. These coolants are made to last for 150,000 miles and have a long service life (or 5 years). It should be mentioned, nevertheless, that German Auto Center and the majority of manufacturers advise cleansing or replacing the coolant every two years.
The metal (Iron) components of the engine and cooling system are protected by traditional coolants, which are IAT coolants and use silicate and phosphate corrosion inhibitors. IAT coolants shouldn’t be utilized because the majority of the iron components in your BMW, Mercedes Benz, Porsche, Mini, Audi, and Volkswagen have been replaced with aluminum and other lighter composites.
It’s crucial to keep in mind that modern German performance cars, whether you drive a Porsche, Mercedes Benz, Mini BMW, Volkswagen, or Audi, will last you for many miles and years if you maintain them properly. German Auto Center in Austin is the place to go for German auto repairs. We will be pleased to help you!