Hydraflush mystery

rmunns · Post by **rmunns** » 12 Sep 2010, 22:46

After reading many times about using Hydraflush to clean Citroen suspension systems,I decided to get some for my Xantia II.

I was in Birmingham (after driving from my home in SW France) last week and duly went down to GSF to get some.

They had not heard of it! After a bit of searching around they announced that the Heathrow branch had some and they could get a 5litre container down to Birmingham the following day.

They did.

What I have is a 5litre container of TOTAL hydraurincage. But on the back it says (paraphrased):

drain - fill with hydraurincage - run for 1500 to 5000km - drain and clean filters - refill with TOTAL LHM PLUS.

It's this last bit that concerns me.

Will this be ok to use with LHM, which is of course what my Xantia has, rather than LHM PLUS?

Dommo · Post by **Dommo** » 12 Sep 2010, 22:52

LHM and LHM Plus are one and the same these days! (or rather, everything is LHM+ these days)

VertVega · Post by **VertVega** » 12 Sep 2010, 23:15

Today I have opened a 5 litre container of TOTAL hydraurincage

LHM+ has better characteristics for extremes (like viscosity values at high and low temperatures).
You can find LHM+ from Total, Bendix, Valvoline, Bosch etc,

rmunns · Post by **rmunns** » 13 Sep 2010, 04:08

Thanks, guys, for the re-assurance.

cachaciero · Post by **cachaciero** » 13 Sep 2010, 10:19

Of course if you wanted a total synthetic version lf LHM you could use LDS

cachaciero

KevMayer · Post by **KevMayer** » 13 Sep 2010, 17:08

Editted by kevmayer due to incorrect and misleading info.

Xaccers · Post by **Xaccers** » 13 Sep 2010, 17:10

KevMayer wrote:I read somewhere that the new LDS is hygroscopic in that it will absorb moistutre from the atmosphere in the same way that brake fluid does.

LHM is not hygroscopic and so can be used in an open system (hence the open reservoir on a Xantia).

That would explain the difference in topping up a C5 and the recommendation for throwing away LDS once it's been opened.

cachaciero · Post by **cachaciero** » 13 Sep 2010, 17:41

KevMayer wrote:I read somewhere that the new LDS is hygroscopic in that it will absorb moistutre from the atmosphere in the same way that brake fluid does.

LHM is not hygroscopic and so can be used in an open system (hence the open reservoir on a Xantia).

Not true LHM and LDS have pretty well identical specifications the only difference is that LHM is a mineral oil based fluid and LDS is semi-synthetic see my previous post on this subject http://www.frenchcarforum.co.uk/forum/v ... hlight=lhm

I believe that the reason the resevoir is sealed on a C5 is to ensure that it runs at a slight vacuum to assist the leak return lines to work.

cachaciero

KevMayer · Post by **KevMayer** » 13 Sep 2010, 17:48

You are right yet again... I've been trying to find what I read to make me believe LDS is hygroscopic.

I just found this info and it says LDS has 'water resistance'...

http://www.eurol.com/custom/producten/p ... d%20GB.pdf

The info also says it should be changed at 5 years or 200,000 kM.

That's another job I need to do. My C5 is just over 8 years old and the LDS hasn't been touched.

Post by **myglaren** » 13 Sep 2010, 17:52

^^Same here I imagine, can't see any record of it being changed.

As LHM doesn't come into contact with other than atmospheric water then I expect any moisture would be evaporated off with the heat it accumulates while the car is running.

cachaciero · Post by **cachaciero** » 13 Sep 2010, 20:06

myglaren wrote:^^Same here I imagine, can't see any record of it being changed.

As LHM doesn't come into contact with other than atmospheric water then I expect any moisture would be evaporated off with the heat it accumulates while the car is running.

Doesn't quite work like that with many oils, heat water and pressure often equal varnish on friction surfaces and sludge formation don't know what LHM does but varnish and sludge sound familiar

In LHM systems the oil works quite hard due to the "crude" method of pressure regulation which puts a lot of heat into the oil even when otherwise no demands are being made on it.

As regards C5 oil changes if the oil looks and smells o.k I don't think I would be bothered to change it. I have worked on big hydraulic systems where normaly samples are taken and chemically analysed every six months or so and usually the oil shows minimal chemical change for several years unless there has been a major component failure and even then the contamination is usually microscopic metalic elements rather than oil failure. So given that by comparison the C5 system is very lightly used I reckon the oil will last the life of the car.

Another issue to consider is that any oil change introduces some degree of contamination done often enough it will choke the filters how much it takes depends on how fine the filters are. On the C5 you can't change the filters..........

cachaciero

Post by **myglaren** » 13 Sep 2010, 20:33

Leave well alone is probably the way forward with C5s then

KevMayer · Post by **KevMayer** » 13 Sep 2010, 21:09

Good stuff cachaciero. Your knowledge never ceases to amaze me. Thanks for the info

cachaciero · Post by **cachaciero** » 13 Sep 2010, 21:47

KevMayer wrote:Good stuff cachaciero. Your knowledge never ceases to amaze me. Thanks for the info

You are welcome Kev.. I understand Methuselah was pretty good too and we are of a similar age.

I have been fortunate that I have lived through a period when England had a varied and rich engineering infra-structure unlike today.
As a result I have gained lots of odd ball bits of knowledge about things mechanical and electrical ranging from submarines systems at the deep end to high flying aircraft systems at the high end with lots of things in the middle.

The C5 is easy by comparison given access to sufficient data, which I have also been fortunate enough to find.

cachaciero

steelcityuk · Post by **steelcityuk** » 14 Sep 2010, 00:36

Hi All,

I can't expand on the extensive knowledge already given but here's what I found on a strip down of an height corrector from my series 1 XM with bright green LHM in the 'tank'-

I don't think you can beat a good strip and clean on valves this old. 40 minutes in a heated Ultrasonic cleaner got it clean!

Steve.