Revised Summary of Citroën Hydraulic Fluids

Conceived and Compiled by Tony Jackson and Mark L. Bardenwerper, Sr.
Updated March, 2016
Home
LHS Cars
Original Fluids For LHS Cars
Alternate Fluids For LHS Cars
Specifications For Fluids Used In LHS Cars

LHM Cars
Original Fluids For LHM Cars
Alternate Fluids For LHM Cars
Specifications For Fluids Used In LHM Cars

Seal Compatibility
Fluid Changes and Flushing
Credits

Editors Note:
Tony Jackson began supplying the Citroën virtual community with this summary many years ago. Since then is has seen numerous edits and modifications. Keeping old cars in running condition is difficult enough, but these Citroens offer the extra challenge of hydropneumatic systems involving braking, steering, suspension and transmission control.

Given the increasing difficulty in finding original specification hydraulic fluids, owners have often relied on ingenuity to devise alternatives. LHS is now made periodically by only one company, Pentosin. The supply is sporatic and prices can vary widely as inventories dwindle. LHM is not available everywhere, though prices seem stable right now. The Fluid Summary is an attempt to provide an updatable source of information on older as well as ongoing trials.

It must be stressed that the authors do not in any way wish to take responsibility for consequences arising from the use of any of this information. Readers are hereby informed that all of this work is fully experimental in nature and any actions taken by readers will be considered as on their own volition. In other words USE THIS INFORMATION AT YOUR OWN RISK.

While original fluids are not always readily at hand, in most cases it is best for your car to use them. One exception might be a car that is undergoing restoration and is prone to leaks.

We invite the Citroën community to offer us information on your efforts. This document is by no means complete or final. As you can see by the following chapters, charts and articles, there are many gaps in our knowledge. Please send your contributions to the authors. It is going through constant changes, so please check back regularly.


Fluids for LHS Cars

Original Fluids For LHS Cars Top
Early production cars used LHV (Liquide Hydraulique Vegetal), a red colored fluid which was basically brake fluid with castor oil thickener. It was sold by several companies, each giving it a different name. There were Castrol HF, Lockheed HD19, Donax D, Energol Hydraulique CF, Pentosin 259 and Stop SP19 and several others. The main hydraulic components were painted black. These fluids proved to be problematic because they were hygroscopic and anything less than frequent fluid changes resulted in corrosion and damage to the system, particularly in humid climates, where it could actually completely break down.

In late 1964, synthetic based LHS (Liquide Hydraulique Synthetique) supplanted the old formula. LHS was apparently manufactured only by Eugene Kuhlmann in France and Deutsche Pentosin Werke in Germany. All other suppliers bought from one of them and packaged under their own labels. Some problems subsided, but hygroscopy was still an issue. A list of approved fluids was issued by Citroen in Technical Note No. 29-D, dated September, 1964. The note also specified four seals that had to be changed to make the cars compatible with the new fluid. The old ones were of natural rubber and the replacements were of EPDM, a newly developed synthetic. Here is a copy of the technical note. Included are the old and new part numbers for the four seals.

Old and new seal numbers (from Tech Note 29-D, September, 1964) and their use
Old Seal Number
New Seal Number
Part Involved
4 929 S
4 986 S
Security Valve (ID)
7 Cylinder Pump (DS)
4 930 S
4 987 S
7 Cylinder Pump (DS)
4 905 S
4 983 S
Rear Wheel Cylinder, Saloon
4 906 S
4 984 S
Rear Wheel Cylinder, Break

Cars sold in the United States and Canada faced more difficulites. None of these fluids were available. Instead, Citroen specified standard brake fluids. Lockheed 70R1 grade fluid was initially listed in the owners' manuals to comply with standardizing Federal regulations. By 1966 the factory approved any fluid complying with specification SAE 70R3, including Mobil Super HD, Delco Super 11, Lockheed Wagner 21B, Mopar Hi Temp. SAE 70R3 was later replaced with DOT 3. Each new fluid provided improvements, especially higher boiling points, but even when DOT 3 came along, it still lacked sufficient viscosity and lubricity for best ride performance, transmission shifting and control of wear.

Everywhere except in the US production changed in 1966 to use a green-dyed mineral fluid, LHM, which did not take up water, and which has proven highly successful ever since. LHM was not compatible with the seals used in cars built previously, so the hydraulic component color was changed to green as a warning. Cars sold in the US changed to LHM in the middle of the 1969 model year due to delays in governmental certification, so consequently, early 1969 model cars in the U.S. still used LHS. Again, the color of the hydraulic components is the tell tale; black is for LHS and green signified that the car used LHM.


LHM was introduced at the following serial numbers for all except U.S. export models LHM for US export models was introduced at the following serial numbers
DS19A-H 4 316 000 DS19A-H 4 330 000
DS19A-M 4 442 000 DS20-H 4 332 001
DS21-H 4 376 200 DS20-M 4 451 001
DS21-M 4 473 100 DS21-H (including cabriolet) 4 621 000
Cabriolet DS21-H 4 376 050 DS21-M (including. cabriolet) 4 490 001
Cabriolet DS21-M 4 473 020 ID19B 3 794 600
Cabriolet Chapron DS21-H 4 376 000 ID20 3 820 001
Cabriolet Chapron DS21-M 4 473 000 Break ID19FA-M 3 546 800
ID19B 3 710 001 Break ID19FHA 3 980 380
Familiale ID19FA 3 535 000 Break ID20F 3 980 501
Break, Ambulance, etc. ID19FA 3 536 000 Break ID20FH 3 985 001
Familiale ID21F 3 554 000 Break ID21F 3 561 600
Break, Ambulance, etc. 21F 3 554 500 Break ID21FH 3 575 350

Factory Seal part number interchange chart for  LHS and LHM vehicles, dated June 1969

Alternate Fluids For LHS Cars Top

Pure Brake Fluid

Standard glycol-based DOT 3, DOT 4 or DOT 5.1 brake fluids work but are less viscous and have poorer lubricant properties than LHS. Rolls Royce used DOT 3 in bottles labeled RR 363 for their application of Citroën patents, but theirs was a much more restricted use of hydraulics. DOT 5 is a newer category for brake fluids that attain a higher dry boiling point. DOT 5 silicone fluid was the first. Later, glycol-based fluids were developed. This fluid was designated DOT 5.1.  DOT 4 and 5.1 may seem better choices because of their higher initial boiling point, but they tend to be more hygroscopic than DOT 3, hence lose thier boiling point faster. 5.1 is also a poorer lubricant.

There are several very good summaries of DOT brake fluids on the Internet. Here are two:
Stop Tech
Moss Motors

This one, in French, is by Yves Frelon and echoes a lot of our observations. Claude would likely be our friend Claude Moritz, who is mentioned below and has done a lot of experiments with PAG:
Rouler en DS liquide rouge, par Claude


DOT 5 Silicone Based Fluid
It is unfortunate that silicone based brake fluid was designated 5 because it causes confusion with DOT 5.1, which is glycol based. Some believe that silicone based DOT 5 fluid might be an improvement as it does not take up water. Experience has shown that if a sytem is at all suspect, all moveable seals should be replaced before conversion. Where seals have already deteriorated, they can fail when the change is made to silicone.

It should be further noted that while silicone DOT 5 does not absorb moisture, it displaces it. Water will still enter the system, but instead of being absorbed into the fluid, it will settle in low places or accumulate in points of low flow. This water can freeze.

Because of the difficulty in avoiding trapped air bubbles, bleeding the system is more difficult. Air in the brakes causes delayed braking action and vagueness.

DOT 5 does not attack paint but it leaves a difficult to remove residue behind that can cause problems with subsequent paint applications.

Even so, several owners have run cars satisfactorily on silicone DOT 5. Some add an additional filter between the pump and reservoir to collect sloughed off material. Some report problems caused by its very high electrical insulating tendencies. Weeping around the brake mushroom can cause trouble with the brake switch. Steps must be taken to isolate this part. One owner installed a pressure activated switch on one of the front calipers. Trouble with contamination of ignition points has also been reported. Many owners convert their systems to electronic, thereby eliminating the points.

Brake Fluid and Castor Oil
Other owners have suggested that the addition of castor oil to the glycol-based fluids improves lubrication and ride without causing harm. This theory is supported by the discovery that the original specification fluids had castor oil additives. In addition to its effect on lubricity the castor oil raises the viscosity to around 35 mPa.sec at 75 deg. Fahrenheit, the same as LHS (plain glycol brake fluid of DOT 3 has a viscosity at this temperature of 23.1 mPa.sec).

This mixture has been used for some time without problems, except in cold climates. If the car is to be used while ambient temperatures are below the freezing point, the castor oil fluid should be drained and replaced with DOT 3 brake fluid and the brakes bled. This is to prevent any castor oil separating out and freezing in lines or components. When warm weather resumes, just add 4 oz. of castor oil. Castrol R racing oil (used by some racing motorcycles) is one source. Model engine or aircraft suppliers are another. Unfortunately, the advent of synthetic oils has made it harder to source. Castor oil is also available in health stores with unpredictable prices.

DOT 4 brake fluid can be used, but has a tendency to absorb water more quickly, so it's boiling point decreases faster than DOT 3. Because it is open to the atmosphere, this is an important consideration in our systems.

Converting to LHM
LHS cars can be converted to LHM if all the seals are replaced with LHM-safe seals. This sounds like a better use of the labour of changing all the seals than switching to DOT 5.1. While their paint color changed from black to green, the metal components actually were not changed when Citroën changed to LHM. Here is a factory seal part number interchange chart for LHS and LHM vehicles, dated June 1969. It might be tempting to leave the original component colors, but to avoid future fluid mixups repainting them to green should not be omitted.

Canola and Rapeseed Oil Based Fluids
Canola (rapeseed) based fluids had the advantage of being safer to handle, did not harm paint and were biodegradable. They were theoretically compatible with both types of seals. Viscosity was high at all temperatures. Texaco, who used to offer a product called Biostar, claimed it was for use between -15 and +80 degrees Celsius. Biostar was more viscous than LHS or LHM at the temperatures for which I have information and had a lower viscosity index than LHM, meaning that viscosity changed more rapidly with temperature. This had a negative effect on suspension damping and shift characteristics on hydraulically shifted cars. Studies also showed that high temperatures accelerated decomposition.

Biostar 32 was nearest to the Citroën specs. However, its rather high pour point and low viscosity index still gave problems when used it in very cold conditions. Biostar is now unavailable, but other companies offer similar products, such as Hydrosafe. The comparison chart, below, now lists the Hydrosafe product rather than Biostar. Note also, there is no specification for boiling point.

Now that rapeseed has been in experimental use for some time, several problems have cropped up. It is proven to be fatal to cars made before 1963 unless every seal has been replaced. This is because those older cars had seals made of natural rubber, which is not compatible. These cars also suffered from decompostion of rubber parts adjacent to hydraulics, such as suspension bump pads. We have now found that some cars that used rapeseed oils have not fared as well due to accelerated wear in moving parts. Even though some owners contunue to use it, for these reasons we can no longer recommend the use of canola base fluids.

PAG and Brake Fluid
Claude Moritz and Mark Bardenwerper have been doing research on the use of the automotive air conditioning lubricant PAG (polyalkylene glycol), mixed with DOT 3 brake fluid. PAG did not freeze or separate in tests we could perform with a household refirgerator/freezer. It is entirely soluble in most brake fluids and the mixtures flow even at extreme low temps. Rubber samples are showing no damage after a year's immersion. One car was run on 10% mixture. However. in the 150 viscosity specification, it is only half as viscous as castor oil, so in order to match LHS, the ratios must be doubled. For now, we are not willing to condone this. We have found higher viscosities available, but only in large quantities to commercial entities.

Still, lubricity is vastly superior to pure brake fluid. It should be noted that PAG is actually used in many brake fluid formulations, particularly DOT 5.1. We do recommend that you test several brands of DOT 3 brake fluid before using to determine solubility.

With the availability of genuine LHS becoming spotty, we must continue our work on viable sustitutes. While each have merit, they also have drawbacks. Pentosin refuses to disclose the formula for LHS, so anything we use must be used with caution. The only thing they have told us is that one of the components is hard to source. That is why we can not recommend the use of any of the substitutes. Unless you are willing to assume the risks of damage to your car or possibly of failures of vital systems, especially the brakes, you should use the factory recommended fluids.

Specifications For Fluids Used In LHS Cars Top
These specifications are harvested from other sites. They are not intended for use as MSDS or true data sheets, as many of these fluids vary greatly by manufacturer!
Characteristics Unit LHM+
For Comparison Only. Do Not Use!
LHS 2 DOT 3
DOT 4
DOT 5.1 DOT 5 Silicone based brake fluid Hydro-Safe ISO-VG-Premium 32 (rapeseed based)
Mark's Mix
9.25% Castor Oil/DOT 3
DOT 3/ PAG 150
10%
Colour - Green Red Amber Amber
Amber Blue/Purple Clear, light amber
Yellow Light Amber
Density at 15C g/cm3 0.830 1.007 ?
1.05 ? .88 ~1 No tests,
Viscosity at -40C cSt <1200 ? 1065
900
900 ? ? But should
Viscosity at 20C cSt ? 32.4 ?
? ? ? 34.7 be about half
Viscosity at 40C cSt 18 14.5-16.5 7.1
? ? 30.7 ? way between
Viscosity at 100C cSt 6.3 4.5-5 2.0 1.5
~1.5
7 6.9 ? DOT 3
Viscosity index - 355 256 30
? ? 199 ? and
Pour point Deg C -62 ? ?
? ? -40 ? LHS
Boiling point
Wet is 3.7% water
Deg C 255 ? 205 dry
140 wet
230 dry
155 wet
260 dry
180 wet
260
See above
? ? Unknown, but should be near DOT 3
Flash point Deg C 135 99 149
? 204 236 ?


Fluid for LHM Cars

Original Fluids For LHM Cars Top
Best is LHM. No other readily available fluid has the same characteristics and any replacement runs the risk of giving rise to behaviour other than that which was originally intended, most particularly in conditions of extreme temperature. It is not difficult to ship in the U.S. and is readily available in Europe.

Properties of LHM+ (the latest version, fully compatible with original LHM). Recommended by Citroën.

Alternate Fluids For LHM Cars Top

Aviation Hydraulic Fluids
Next best is what is known in the aviation community as "red oil" (MIL-H-5606). It is cheap to buy and is just slightly lower in viscosity. Having existed before LHM, it's reasonable to believe that Citroën would have allowed it if they thought it delivered what they required. But the demands of the Citroën system are unique and very specific. It is also conceivable that they were concerned with the color similarity of LHS, a potential disaster for older car owners, should incompatible fluids be accidentally intermixed.

The actual specifications for LHM differed from the earlier version of "red oil" in one important aspect, VI (viscosity index). The VI represents how much a fluid's viscosity changes with temperature. The higher the number, the more constant the viscosity will remain across a given temperature range. As of 2/97, MilSpec 5606(F) was supplanted by 5606(G). The major improvement was in the area of low temperature viscosity. Since then, the specification has again changed and is now (H). The VI for LHM is over 350, while the older 5606(F) red oil was around 300. The VI of the new MIL-H-5606(H) is now above 370, surpassing LHM. For comparison, the VI for Dexron (regardless of type) is only about 200. However,  the viscosity of red oil is lower than LHM at all temperatures.

A comparison of MilSpec 5606(H) and LHM+:
Dexron Automatic Transmission Fluid
Third best is Dexron automatic transmission fluid. More than twice as viscous as LHM at low temperatures, Dexron may be problematic in cold conditions. Steve Hammond of Citraulics in the U.S. had this to say about the use of Dexron. "The original Dexron that was used 40 years ago could cause measurable wear to three principal components in the car-the pump, the height corrector slide valves and power steering control valves. However, that has not been the case since the introduction of Dexron II. The current version, Dexron IV, is classified as a compatible 'hydraulic fluid' by most all of the major hydraulic pump manufactures such as Vickers and others. The only problem with Dexron III or IV is its viscosity index (VI). It is not high enough for normal use in a hydraulically shifted (BVH) car. IOW its change in flow characteristics with temperature changes is beyond the adjustment range designed into the BVH system to produce the shifting results and consistency the system is designed to provide."

Here is a comparison of Dexron:
Motor Oil
30 weight engine oil can be used for emergencies only, as it will not attack the seals in a LHM car. However it does not have the high pressure shear characteristics of quality hydraulic fluids nor a sufficiently high viscosity index as well as other necessary properties for long term use.

Kendall Hyken Blue
Several owners are using a hydraulic fluid made by Kendall called Hyken Glacial Blue. Usually well behaved, it reportedly gets thin in hot climates causing abrupt shifts in BVH cars. Others have used Exxon's Univis 13. Some Mercedes and BMW cars use a fluid called Pentosin CHF. We've found two versions of this, and both look to be suitable for use in later D series suspensions (they are even green) according to the information we have. They are usually quite expensive! Mercedes uses a fluid called ZH-M in some of their cars for power steering and self-leveling rear suspensions. This fluid, while almost certainly harmless to seals in Citroën cars, has a lower viscosity index and its viscosity is generally lower than that of LHM. This would demand more work of the high pressure pump and would have some effect on suspension behaviour. It might also be a bit marginal in high ambient temperatures, or when the brakes were really punished, as when descending a long mountain pass. It is, however, probably a better option that Dexron (see below). It is cheaper than the Pentosin CHF fluids but costlier than Dexron. We have added that data to the chart below, though so far there are no confirmations of owners' experiences.

Lubriplate 70
Several hydraulic fluids developed to replace petroleum based fluids have become more economically viable in recent years. One of the most recent is Lubriplate 70. It as a favorable viscosity index, a very low pour point and is readily available at least in the United States, where LHM is more hard to find. It has only one drawback that we have found so far. It is nearly clear and is hard to see in the stand pipe on the reservoir. Some have considered using some type of dye. Most likely any type of dye used in petroleum products could be used. Of course, the preferred color would be green!

Conclusions
Generally speaking, the vast majority of mineral oil based hydraulic fluids are fully compatible with the seals in LHM cars. I have added Shell Tellus to the list below for comparison purposes. However, most of them do not have viscosity characteristics the hydraulic systems were designed for. They can adversely effect shift characteristics in (BVH) equipped cars and if extreme, will even cause suspension behavior and steering problems. Fluids with low VI will cause problems with temperature fluctuations. A good minimum would be 280. LHS2 has a VI index of 280 and a cST rating of 14 at 40c. LHM+ has VI index of 350 and a cST value of 18 at 40C. When the factory went from LHS2 to LHM the only thing that was changed was the rubber seal composition. The actual design of the various hydraulic components remained unchanged. There is sufficient allowance in the system design that a change in fluid cST at 40C from 12 to 20 will have little to no effect on basic performance or system feel.

Specifications For Fluids Used In LHM Cars Top
These specifications are harvested from other sites. They are not intended for use as MSDS or true data sheets!
Characteristics Units LHM+ Pentosin
CHF 7.1
Pentosin
CHF 11S
ATF+3 Texaco
MIL-H-5606 (H)
ARAL Vitamol ZH-M Shell Tellus 22 Exxon Univis  13 Kendall  Hyken  Glacial Blue Lubriplate 70
Colour - Green Green Green Red Red Green
Red
Blue Pale Yellow
Density at 15C Kg/L 0.830 0.857 0.825 0.825 0.86 .861 .866
.855 .87
Viscosity at -40C cSt <1200 1050 <1100 1500 600 6000 (?)
371 2840

Viscosity at -20C cSt

230




240

Viscosity at 0C cSt
75



180 338

Viscosity at 20C cSt
32


~32



Viscosity at 40C cSt 18 18 18.6 36.8 13.2 16 22 13.5 14.9 16
Viscosity at 50C cSt
14.3







Viscosity at 100C cSt 6.3 6.0 >6 7.65 5.0 ~4.2 4.3 5.3 4.4 6
Viscosity index - 355 326 320 185 370 181 100 404 233 340
Pour point Deg C -62 -62 <-62 -45 -60 -40 -30 -60 -60 -56.7
Boiling point Deg C 255







288
Flash point Deg C 135


82 140 204 100 170 93.3

Seal Compatibility Top
A seal's compatibility is determined by its durability in the fluid that it must operate in. The systems that we are concerned with use glycols (normal brake fluid) or petroleum (paraffin /mineral oil/others) or synthetics fundamentally designed to supplant them. Seals come in many shapes. Automatic transmissions have "O" and square rings, flanged, or lip seals and gaskets. Primarily, the hydraulic systems in our cars use o-rings and protective covers such as those found on the ends of the height correctors and in the suspension ram boots. But seals can also be made of other elastomers, metal, paper or other fiber products, or specialized plastics such as teflon.

For glycol based fluids the material of choice is ethylene propylene (epm, pdm, epdm). Introduced in 1964, it still has the best resistance to brake fluid. A new compound that has been recently introduced and shows promise as being suitable for both glycol and petroleum based fluid is Aflas (TFE Propylene/trademarked 3M).

For Petroleum based fluids (LHM, Dexron, 5606 Spec, etc.) the following materials are the most widely used: Fluorocarbon based, (Vinylidene fluoride-hexafluoropropylene) also know under the trade name Viton (and others) and Nitrile (NBR or Buna N, Acrylonitrile-Butadiene Copolymers). Of the two Viton has the best mechanical strength/temperature resistance and is much more expensive compared to Buna N. While there are others, the above two are the most common.

The seals in our cars are of two types-static and dynamic. Static seals are those where the sealing faces do not move. Dynamic seals are those where one or more of the sealing faces moves relative to the other. To list a few, the power steering rack, suspension cylinders, brake pistons, clutch engagement control/steering speed control (in SM's), height control valves, rear brake articulating joints on ID/DS series are all examples of dynamic sealing points. The high pressure pump has one dynamic seal, though it is a metal to metal seal at its driveshaft. The suspension sphere diaphragm is a special kind of seal and presents real problems from a design standpoint. Not only must it be resistant to the fluid in use, it also has to have extremely low gas permeability, excellent flexibility and tear resistance over a wide range of temperatures and pressures.

When Citroën introduced LHM in 1966, they encountered serious high temperature problems with the diaphragm material during the first couple of years, primarily with gas permeation. This problem has been almost completely eliminated in the latest cars, such as the C5. The diaphragms are now 2 ply.

These are the three commonly found compounds in our systems built since the introduction of LHS and their usage (earlier cars used natural rubber)

More complete information on seal compatibility can be found at Engineering Fundamentals and Marco Rubber.

Fluid Changes and Flushing Top
Before we close we'd like to address the issue of fluid changes. Flushing instructions can be found here. This old brochure was written before LHM was put into use. For later cars, the procedures are much the same (later cars have a drain tube on the reservoir). Just substitute the proper fluids for those stated. Though owners of LHS cars should already know that they must make frequent changes because of hygroscopy, the fluids used in later cars also degrade with use. The long chain polymers that are used to improve viscosity and provide lubrication under extreme pressure begin to break down. This is caused by the physical shearing of these chains as the fluid is pumped under high pressure throughout the system. Furthermore, corrosion can occur in later cars, too. Anti-oxidant additives have a finite life. Once they become ineffective, the polymers oxidize and change their characteristics. Moisture trapped in the system will cause corrosion. Dirt and other particles collect in the system and accelerate wear. Keep in mind that just because the fluid looks "clean" does not mean that it is providing optimum protection. The factory recommendation of a change every 24,000 miles/40,000km is not overly restrictive for LHM cars.

LHM systems use a flushing agent called "Hydraurincage" ("hydro-rinse-ahj"). It can be used full strength for full effect, or it can be mixed. Hydraurincage can be left in the system for as long as 3,000 miles/5,000km. before it needs to be removed and fresh fluid installed. It can be hard to find in the US in particular, but Citroen part suppliers stock it. It does not need to be used frequently. It is most effective on cars that have been taken out of long storage or that have had a history of neglect. When in the system, frequent filter cleanings will be needed. Gasoline can be used to clean components (use great care) or mineral spirits.

Never use Hydraurincage in cars using LHS fluid.

Those with D's with glycol-based fluids (LHS) need to be more diligent regarding changes. When the car rises, fluid moves out of the reservoir drawing air in. Moisture in the air is absorbed by the fluid. This problem is aggravated in moist climates and lessened in dry greatly increases the potential for corrosion in the system-especially on parts and areas where there is little movement of the fluid, such as wheel cylinders. High moisture content drastically lowers boiling point of your fluid which can braking dangerous as it actually can turn into compressible vapor. Several owners have tried alternative fluids to counteract these problems. Like LHM, viscosity modifiers, lubrication additives and corrosion inhibitors all degrade over time. All these things happen faster in our cars than in typical closed systems. Because of higher working pressures, constant circulation and influx of moisture laden air, the factory recommended change interval was 18,000 miles/30,000 km. We recommend every two years in dry climates and light use and every year in humid conditions or heavy use regardless of mileage. In cars that are not used frequently, those intervals might be extended.

The flushing agent specified by Citroen for LHS cars is hexylene glycol. It should only be left in for 20 miles/30km if used full strength. Mark Bardenwerper used it in a U.S. specification ID 19 with excellent results. As it was rather expensive, he drained and added only about a quart instead of a complete change and left it in for double the time. He did have to clean his filter a few extra times. His steering had better feel and power, for one thing.

Some owners used pure brake fluid and a little alcohol. I would not recommend using alcohol as it will not lubricate at all and could cause damage, though alcohol or soapy water can also be used to clean LHS components during repairs (parts must be thoroughly dried before reassembly).

Credits Top
Image courtesy Pomini Paolo

Special thanks to John Titus, Stan George, Alastair Macintosh, Adam Reif, Shane Leviston, Bob Dircks, Brad Putchat, Jan Forrest, Maurice Gunderson, Steve Hammond, Ulf Petermann, Dale Ice, Jack Shotton, Jint Nijman, Carter Willey, Nils Oehler,  Claude Moritz and the selfless contributions of the Citroën List communities found at Dseries-L and citroen-dsid. This is truly a world class effort!

Copyright 2016, Tony Jackson and Mark L. Bardenwerper, Sr.

Please send suggestions to Mark or Tony.

It must be stressed that the authors do not in any way wish to take responsibility for consequences arising from the use of any of this information. Readers are hereby informed that all of this work is fully experimental in nature, and any actions taken by the readers are taken on their own volition. In other words USE THIS INFORMATION AT YOUR OWN RISK!

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