POWER STEERING FLUIDS

As with engine oil, there are many different PAS hydraulic fluid specifications. Mixing incompatible fluids together can cause serious damage, not least to the system’s rubber seals. While you should heed the specifications given in your car handbook, advice about manufacturerbranded fluid can be unhelpful, especially if it has become obsolete.

In general, three types of fluid are available. The most commonly used automatic transmission fluid (ATF) is usually red in colour; several grades are manufactured, but they tend to be compatible with each other. However, double-check with your supplier.

Designed specifically to be exposed to higher temperatures and loads than ATF, central hydraulic fluid (CHF) has usually a light yellow hue, although some different colours exist. CHF tends to be used more commonly with electro-hydraulic systems.

Finally, liquide hydraulique minéral (LHM) is used on very old Citroëns, the last of which was the Xantia. C5/C6 models especially used liquide hydraulique synthétique (LHS), a type of CHF made by Total Lubricants.