Hydraflush.

XantiaJon · Post by **XantiaJon** » 27 Apr 2006, 13:40

Can anybody tell me the procedure for Hydraflushing a Xantia? Thanks

f00lzz · Post by **f00lzz** » 27 Apr 2006, 16:32

A quick search on the database will reveal masses of info about doing the change.... with lots of tips from people who have actually done the job!!

Barbarian · Post by **Barbarian** » 28 Apr 2006, 08:28

what is a hydraflush?

Ross_K · Post by **Ross_K** » 28 Apr 2006, 11:03

Barbarian wrote:what is a hydraflush?

Think of it as an enema for your car.

Barbarian · Post by **Barbarian** » 28 Apr 2006, 12:38

Im still not any clearer

Ross_K · Post by **Ross_K** » 28 Apr 2006, 12:49

It cleans the gunk out of the pipes.

You empty out all your LHM, stick the hydraflush in and drive around for a couple of thousand km's. Empty and refill with LHM, and Bob's your dad's brother.

Or get an idea here:
http://www.citroenz.com/BX/flushfluid.html

Barbarian · Post by **Barbarian** » 28 Apr 2006, 13:44

Right so its for the suspention system. is it only hydroactive cars that need this or is all xantias?

fivelighters · Post by **fivelighters** » 28 Apr 2006, 14:07

and Bob's your dad's brother.

and mary is ur mums aunt

deian · Post by **deian** » 28 Apr 2006, 14:43

what i don't get it... it's all well and good changing the LHM for Hydraflush in the resevoir, but how about the rest of the system like in the pipes and inside the spheres etc? How much LHM actually goes back into the resevoir when you depressurize? I guess there would be about 20% left in the system, so putting hydraflush in you wouldn't have 100% Hydraflush would you. Same goes for LHM afterwards, to swap the old for the new you would have to drain/replace repeatedly right?

Mandrake · Post by **Mandrake** » 28 Apr 2006, 22:04

deian wrote:what i don't get it... it's all well and good changing the LHM for Hydraflush in the resevoir, but how about the rest of the system like in the pipes and inside the spheres etc? How much LHM actually goes back into the resevoir when you depressurize? I guess there would be about 20% left in the system, so putting hydraflush in you wouldn't have 100% Hydraflush would you. Same goes for LHM afterwards, to swap the old for the new you would have to drain/replace repeatedly right?

The same is true of an engine oil change though - you're never getting 100% of the old oil out...which is why - just like engine oil, its a good idea to do it on a regular schedule so it is getting replaced BEFORE it gets disgustingly dirty...(3 years seems to be a reasonable amount of time between LHM changes)

The hydraulic system in a Xantia contains 5.4 litres of oil and of that approximately half a litre stays in the system in the piping when you depresurize and empty the tank, (you could work it out exactly by measuring the amount you tip out of the tank....) so you're changing about 90% of the oil.

Thats the main idea about hydraflush - if the oil you're changing was changed on schedule and is relatively clean, you don't need to hydraflush - just replace with LHM and the 10% that was left of the old oil is not bad enough to worry about and will be diluted, and blend together thus lowering the impurity concentration by a factor of 10 after it has fully mixed.

But if you're replacing oil that is either the wrong oil (for example some people seem to put ATF in the hydraulic system...

) or is disgustingly dirty, then leaving that 10% in there will still contaminate the system, so you then hydraflush.

The first hydraflush change dilutes the original oil down to 10% of the total and mixes with it. Also hydraflush has an additive in it which is able to scour the hydraulic system for particles of dirt and grit and put them into (fluid) suspension so that they will circulate and eventually be removed.

You run for a few thousand miles with hyraflush in to allow the 10% of original oil to fully blend with the hydraflush and give it time to do its cleaning action, then you change back to normal LHM, and once again you are replacing 90% of what you now have with fresh oil.

The original oil that you were trying to get rid of is now theoretically diluted down to 10% of 10% eg 1%.

Hope that makes sense.

Regards,
Simon

deian · Post by **deian** » 28 Apr 2006, 22:35

yes, so it's a good idea to hydraflush mine then, becuase the fluid is clear but a bit yellow, i want proper alien green Citroen blood in mine!

thanks mandrake mate

Mandrake · Post by **Mandrake** » 28 Apr 2006, 22:51

Bear in mind that hydraflush is not green - its an orange (yellowish?) colour, so you may already have a bit of hydraflush in your car...and going from hydraflush to LHM won't give a pure green colour due to the blending of 10% of orange coloured liquid.

Regards,
Simon

_kid_ · Post by **_kid_** » 28 Apr 2006, 23:03

Just a thought

Is it possible to suck up the LHM (like the dealers suck up engine oil through the level stick) through the opening at the top of the tank.

It would save taking it to pieces, esp. if doing hydroflush and then LHM

howiedean · Post by **howiedean** » 28 Apr 2006, 23:05

Mandrake wrote:Bear in mind that hydraflush is not green - its an orange (yellowish?) colour, so you may already have a bit of hydraflush in your car...and going from hydraflush to LHM won't give a pure green colour due to the blending of 10% of orange coloured liquid.

Regards,
Simon

One thing I've noticed as well is that not all LHM is exactly the same colour from the bottle. I try to use TOTAL LHM now as it's the darkest green and therefore easier to tell when the fluid needs changing.

Mandrake · Post by **Mandrake** » 28 Apr 2006, 23:09

_kid_ wrote:Just a thought

Is it possible to suck up the LHM (like the dealers suck up engine oil through the level stick) through the opening at the top of the tank.

It would save taking it to pieces, esp. if doing hydroflush and then LHM

While you could syphon the oil out of the tank (in fact its recommended, so that you dont make a mess when trying to get the tank out) I don't see what it achieves - you're not just trying to replace the oil, you're also trying to clean the tank and the filters.

So you still HAVE to take the centre of the tank out to clean the filters.

Also, just draining the oil out of the tank doesn't clean it... it will still be full of sludge, and in fact there is a plate at the bottom of the tank which acts like a "sludge trap" on purpose, it lets all the particules of crap settle under the plate so they don't keep getting sucked up by the pump and pumped back into the system.

Think of it like silt at the bottom of a pond. This has to be cleaned out as well. So just "sucking" the oil out is not going to do a proper job of cleaning the system...

BTW if you're talking about trying to suck the oil from the piping within the car, you won't get very far with that either, as the high pressure lines you're trying to suck the oil out of are air tight, so there is no way you can suck them. (Sucking relies on air being able to enter at the other end...) Also you have many dead ends, for example the brake lines and the front suspension struts...

Regards,
Simon