The red and green hydraulic system:

The hydraulic system of the ID/DS can be devided into two different systems.

Red system (LHS):
The so called red system that has been used from 1955 until September 1966, got it's name because the original red hydraulic oil was colored slightly red. This synthetic oil is marked LHS (Liquide Hydraulique Synthťtique) and is very aggressive. It's like a paint remover. Besides that, the oil is very hygroscopic, with means that it takes up moisture from the air. The oil loses it's characteristics during time and can affect the internal hydraulic organs. The LHS oil needs to be replaced every 3 years to prevent corrosion problems in the hydraulic system.

Hydropneumatische veringBetween 1964 and 1966, the LHS oil has been gradually replaced by the colorless LHS2 oil. Cars with a so called red system can be recognized by the fact that all hydraulic parts are black, like suspension spheres, oil container, high pressure pump and power steering (DS). Both kinds of LHS oil can be mixed without problems. The LHS oil is almost not available anymore. The LHS2 oil is available at the shop of the CitroŽn ID/DS Club Nederland.

Green system (LHM):
Green suspension spherel In September 1965 CitroŽn switches over to the so called green system. This system uses a mineral oil with the marking LHM (Liquide Hydraulique Minťral). This oil is slightly green, not hygroscopic, and not aggressive for paint. Because both kind of oil use different gaskets, they may never be mixed. This leads to severe damage to the hydraulic system.
In order to prevent this, all hydraulic components of the LHM system have been painted green.

The LHM oil is still used by CitroŽn today in the new models like the Xantia, XM and the latest C5. The oil is available at all bigger fuel stations.

About the red system the opinion varies strongly. Some people will never want to have a cars with a LHS system because it's known for it's problems with the gaskets. Others praise the red system for it's smooth suspension.
When you take good care of the LHS system, and renew the oil every three years, many problems can be prevented.

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