Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
ZF Ball and Nut Power Steering with H31 System
The approved oils for BMW models with power steering and the H31 brake booster system are identical with those oils approved for power steering without the H31 system except for the following:
E32 models with self-leveling rear suspension and mutual oil supply tank in the engine compartment (see INTEGRATED SUSPENSION SYSTEMS ).
Countries with very low outside temperatures (e.g. Canada) had their power steering systems filled at the factory with Pentosin CHF 7.1 since 9/87 through 9/91. This is also to be used on vehicles built before 9/87.
Since 9/91, vehicles now use Pentosin CHF 11S instead of CHF 7.1.
| Pentosin CHF 7.1 | BMW Part No. 81 22 1 468 879 |
| Pentosin CHF 11S | BMW Part No. 83 29 0 429 576 |
These cars are marked with a pertinent label located close to the oil tank.
LHM oils (green color) of the following manufacturers may also be used instead of Pentosin (CHF 7.1):
Shell LHM
Castrol LHM
Exxon LHM
The mixing of CHF, LHM oils and ATF is not permitted.
Pentosin CHF 4548 was used on vehicles built before 9/87 but is no longer available. However, mixing of Pentosin CHF 7.1 with residual quantities of Pentosin CHF 4548 are permitted in these earlier vehicles. Mixing of these two oils is not permitted for E32 / E38 vehicles.
The hydraulic system for power steering and power-assisted brakes must be drained as completely as possible when changing from one type of oil to the other.
All oil supply reservoirs are marked with the type of oil being used - ATF or CHF.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.