auto box reliability

[DickieG]

the LHM still has a bit of a yellowy tinge to it

Clean, uncontaminated LHM does turn yellow in time.

Mine turned from green to yellow in a few days after I did the initial change

That doesn't sound quite right Simon, it normally stays green for some time, as per your Father's Xantia even if the fluid taken out was well past its best. It might well be worth putting some Hydraflush through it as it sounds as if there has been some sort of contaminant used in the past.

The process of LHM turning yellow only appears to occur during usage, presumably due to contamination from the rubber pipes or breakdown of the molecules through pumping/pressure.

[LeeDJC]

Clean, uncontaminated LHM does turn yellow in time.

Mine turned from green to yellow in a few days after I did the initial change

That doesn't sound quite right Simon, it normally stays green for some time, as per your Father's Xantia even if the fluid taken out was well past its best. It might well be worth putting some Hydraflush through it as it sounds as if there has been some sort of contaminant used in the past.

The process of LHM turning yellow only appears to occur during usage, presumably due to contamination from the rubber pipes or breakdown of the molecules through pumping/pressure.

I agree with DickieG.

I did a 1000mile hydraflush, changed the fluid, bled all the brakes etc, and it's still the same bright green after 15k miles and 12 months.

[Mandrake]

Clean, uncontaminated LHM does turn yellow in time.

Mine turned from green to yellow in a few days after I did the initial change

That doesn't sound quite right Simon, it normally stays green for some time, as per your Father's Xantia even if the fluid taken out was well past its best. It might well be worth putting some Hydraflush through it as it sounds as if there has been some sort of contaminant used in the past.

Hi Dickie,

You must have missed the bit where I said the entire LHM system was full of RED oil when I got the car (probably Dex III)

I've only done one change to LHM so far, and when you do an LHM change about 10% of the oil cant be changed due to the amount sitting in piping etc, so its natural for the 10% of old oil and 90% of new oil to blend together after a few days/weeks.

(Mix green and red together and you get - yellow...)

Hydraflush is not available where I am, I'm just going to do another drain and change to fresh LHM and this time the contaimanent level should drop from 10% to 1% which should be enough to lose the yellow colour.

The process of LHM turning yellow only appears to occur during usage, presumably due to contamination from the rubber pipes or breakdown of the molecules through pumping/pressure.

As I said - I've never seen this before, on nearly a dozen Citroen's I've had something to do with over the years.... generally the oil just tends to get darker and dirtier, but doesn't lose its basic green colour...

Perhaps the change in colour comes from the fact that Hydraflushing seems to be common over in the UK? Since Hydraflush is orange (?) once its been in the system its hard to get it 100% out. And gradually any remaining hydraflush will blend with the LHM and start to change the colour.

Over here nobody has ever heard of Hydraflush and I've never seen it used, so perhaps that explains why I havn't seen this colour change phenomen before.

Regards,
Simon

[DickieG]

You must have missed the bit where I said the entire LHM system was full of RED oil when I got the car (probably Dex III)

Yes I forgot the earlier posting, Doh!

The strange thing about LHM is that irrespective of whether Hydraflush is used or not, in time through usage LHM changes colour from bright luminous green, to yellow before it eventually turns black.

In case you weren't aware, Hydraflush is produced by Total if you were looking to source some over there. I take it carriage from the UK would be too expensive due to the weight.