Home » BMW Power Steering Fluid Type ATF or CHF 11S
BMW Power Steering Fluid Type ATF or CHF 11S

BMW Power Steering Fluid Type ATF or CHF 11S

What color power steering fluid does your BMW take? The answer to that question depends on the year your model was produced and other factors, but the colors are typically red or green.

Red power steering fluid is ATF. Green is CHF-11S.

CHF stands for “central hydraulic fluid.” It’s what should be found in late-model BMW vehicles, including the M5 or the E38 750iL.

ATF is not a regular power steering fluid, although it sometimes gets treated as such. Your vehicle should indicate in the owner’s manual or on the cap what product to use.

BMW Power Steering Fluid Type ATF or CHF 11S

BMW power steering fluid type CHF-11S is the preferred option over ATF, especially for models produced in the 1990s. ATF has a reputation for slowly destroying a vehicle’s hydraulic seals. CHF-11S has a bright green color compared to the red ATF fluid, making it easy to identify the difference between the two.

ATF and CHF-11S are not exclusive to BMW vehicles. These options are available across virtually all makes and models today.

When BMW uses CHF, it is because the power steering pump also drives hydraulic systems in the vehicle beyond the steering gear.

Some models have a tandem vane pump, which is a component that supplies several circuits simultaneously during operation.

Other BMW models feature a regulator that can split the solo pump output into multiple circuits for a smooth and efficient driving experience.

If you own the BMW E31 8-Series, a hydraulic circuit receives CHF support for the power brake assist feature. For the 750iL or the M5 with self-leveling suspensions, the rear has hydraulic elements that require CHF support.

Vehicles from other automakers with a feature called “active body control” follow the same principles and require hydraulic support at each corner.

It’s like the way a vehicle’s brake master cylinder feeds fluid to each caliper, relying on the same reservoir for all the circuits requiring fluid.

Why Shouldn’t I Use ATF in a Vehicle That Needs CHF?

Although ATF and CHF provide one similar service (power steering support), it is not the same kind of fluid.

Unless your BMW specifically calls for ATF, you should purchase CHF to manage your hydraulic systems.

You don’t want to mix oils when operating a vehicle. ATF is known to weaken the diaphragm and hydraulic seals of the self-leveling suspension’s nitrogen-filled accumulators.

As the vehicle gets driven, the rear suspension loses much of its support. That causes it to become harder and looser during operation. If you have the E31-E32 hydraulic braking system, you can also lose instant stopping force.

Since replacing the hydraulic accumulators is a relatively expensive repair compared to using the correct fluid, it’s always better to see if you need either ATF r CHF for your BMW.

I Just Bought a BMW – Should I Have It Checked?

If you recently purchased a second-hand BMW, it is a good practice to check the fluid color in your vehicle. It is not unusual to see someone using ATF when they should have been using CHF 7.1 or 11S.

The easiest way to correct this situation is to pump it out of the reservoir. Even if the fluid looks old and dirty, replacing the liquid with something new and letting the engine move it around can help things a lot.

You might need to repeat the fluid transfer two or three times until the product is mostly new in the vehicle.

Although this methodology is a little wasteful, the BMW’s design doesn’t make fluid replacement an easy task.

There isn’t a simple drain plug to pull to correct the situation. That means lots of ATF or CHF gets stuck in the hydraulic components since it doesn’t run to a central location.

That means this servicing option is the only way to reliably ensure that you do not have incorrect fluid potentially damaging your suspension’s components.

Can I Use ATF in My BMW?

Unless you are specifically instructed to use ATF in your BMW by the owner’s manual or the components under the hood, you should have CHF in your vehicle.

If your BMW was built in 1990 or before, your best option is to use Pentosin CHF 7.1. For all newer models, Pentosin CHF-11S is the preferred product for your power steering and hydraulics.

You can tell what product to use by looking at the top of the power steering fluid cap. If you don’t have access to CHF, you’ll need to use an alternative that offers the same qualities and features.

What Power Steering Fluid Should I Purchase?

The best product for a modern BMW is Pentosin CHF 11S. It’s a long-life synthetic hydraulic fluid that works well in other makes and models. You’ll receive one liter per container, which means you’ll need three to do a complete flush and replacement.

If you purchased a BMW that used ATF instead of CHF 11S, it may take nine containers to fully remove the dark red liquid that shouldn’t be in your vehicle.

CHF 11S is specially formulated to work with multiple automotive hydraulic systems. It provides support for your central lock systems, leveling control, shock absorption, suspensions, and convertible top hydraulics.

You can use this product in summer or winter conditions with its temperature range from -40°F (-40°C) to over 266°F (130°C).

Pentosin follows a zero-mistake policy, requiring the liquids to meet the OE standards of your BMW.

The company was founded in 1927, eventually growing as one of the world’s best innovators of mineral and synthetic oil-based fluids to help vehicles stay on the road longer.

All Pentosin products strive to deliver superior performance to ensure system longevity.

Although you could top off your power steering fluid system with this option, vehicles typically perform better when using the same liquid.

Ingredients Found in Pentosin CHF 11S

Pentosin CHF 11S uses hydrocarbons to create an effective power steering fluid and hydraulic support liquid for BMW vehicles and other models.

It uses three hydraulic fluids in its mix to create the consistent results that drivers need when hitting the road.

  • CAS-No. 8042-47-5 (base oil, low viscous)
  • CAS-No. 68549-11-6 (synthetic oil, low viscous)
  • CAS-No. 72623-86-0 (base oil, low viscous)

It helps to wear a respirator or breathing protection that stops accidental inhalation of liquid mists when pouring this product. Move to fresh air if you happen to inhale anything. If accidentally swallowed, don’t induce vomiting. Contact your doctor or the poison control line immediately.

This product, like most automotive fluids, should be kept out of the reach of children.

Product Attributes of Pentosin CHF 11S

Density at 20°C825 kg per cubic meter
Kinematic Viscosity at 100°C6 mm squared per second
Kinematic Viscosity at 40°C18.7 mm squared per second
Kinematic Viscosity at -40°C1100 mm squared per second
Viscosity Index313
Pour Point-70.6°F (57°C)
Flash Point320°F (160°C)
Ignition Temperature455°F (235°C)

You can purchase Pentosin CHF 11S in one-, five-, or twenty-liter containers. It is a BMW-approved product.

How to Change the Power Steering Fluid in My BMW

The unfortunate part about changing the power steering fluid in BMWs, especially the E36, is that the reservoir is almost underneath the intake manifold. Even if you want to take a good look at what you’re working with when updating your vehicle, a few parts need to come out.

You’ll need to remove the intake box, MAF sensor, and potentially the alternator cooling duct. That should give you sufficient room to work on things, but it ultimately depends on your model and its configuration.

Always refer to your owner’s manual for the specific steps you should follow to change the power steering fluid.

This information is a generalized step-by-step approach that may require modification to be successful.

  1. You’ll need to lift the front of your BMW. Use a hydraulic jack at the appropriate point to achieve enough lift to place jack stands underneath the vehicle. Refer to the owner’s manual for the specific steps to follow in this area for your model.
  2. Wrap your power steering pulley, belt, and anything close to the power steering fluid with plastic wrap. This step prevents the liquid from contaminating these components.
  3. Remove the reservoir cap.
  4. You’ll need to suck fluid out of the system using a pump or a syringe. This liquid will not be reused, so you’ll need a collection plan and a way to dispose of the materials safely.
  5. Remove the 22 mm banjo bolt underneath the power steering pump to let the fluid drain out of it from there.
  6. Turn the key in the ignition so that the steering wheel unlocks, but do not start your BMW.
  7. Rotate the wheels back and forth from the furthest left to the furthest right. You’ll need to repeat a few times to push the remaining fluid out of the system. At this point, your reservoir should be empty, and there should not be any liquid dripping from the PS pump fitting.
  8. Reconnect the hose to the power steering pump. Put in new crush washers for the banjo bolt fitting, which you’ll need to have torqued to 30 foot-pounds. If you can’t fit a torque wrench in there, keep tightening it until the washers start to pinch.
  9. Fill the power steering reservoir with the appropriate fluid.

If you purchased a second-hand BMW that used ATF instead of CHF for the power steering fluid, you might need to repeat these steps two or three times to remove the majority of the unwanted red liquid from your system.

Do not try to wash it out or use alternative products other than CHF to complete this update. You could inadvertently cause even more damage to occur.

Using CHF 11S Is Your Best Option in Almost Any Circumstance

Although ATF is conceivably a short-term solution if drivers don’t have access to CHF, the time it takes to replace it is considerable. Alternative synthetic products are available from other brands, but these should also be removed as soon as possible to maximize a vehicle’s lifespan.

When I bought my first car, it was a used model from a local dealership. It looked great, ran well, and had about 60,000 miles on it.

For the first few weeks, everything worked great. I got tons of compliments about how the vehicle looked, and I spent some time each weekend polishing it up.

That’s when the steering wheel started producing a grinding noise when I’d turn.

At first, I thought it was the power steering fluid. The reservoir was a bit low, so I topped everything off. Once the air worked its way out of the system, I figured everything would be fine.

After a couple of days, the grinding noise got worse. Since it was happening when I’d turn the steering wheel, I thought maybe it was the tie rod ends, but they looked good. I had the CV joints and the brake rotors inspected, and they also passed.

The issue turned out to be my wheel bearings. Once they were replaced, everything worked well without that terrible sound when I turned.

I cannot stress enough that any power steering or hydraulic issue should be inspected right away. Whether you do the work yourself, let the dealership handle things, or work with a certified mechanic, it is better to have answers than to guess.

Then remember to use Pentosin CHF 11S for the best results.


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