Is Old Lhm Reusable?

This is carrying on my at questions about LHM and parafin etc.

Last week I switched from LHM to Hydraflush in my J reg 2.1d that I've just acquired - the old LHM was a horrible colour and suspension was harsh and dead.

I left it the old LHM standing a week and a lot of sediment has dropped but it is still a very dark green. Then I put it through 2 coffee filters into a glass bottle to see if anything else could be strained out and the answer as far as I can see is no. The liquid is still very dark green and as far as I can see, there is no visible sediment left on the filters.

I suppose this might mean one of two things:

1) there is stuff still suspended but the particles are small enough to pass through two coffee filters;

2) the actual composition of the LHM has in some way been changed and this is reflected by a change in colour.

I'm assuming the answer is 2 but I'd like to be able to filter the stuff in the interests of ecology/stinginess and am wondering if there is a cut-off point, beyond which LHM loses its properties. Does anyone know?

Incidentally the spare parts man Citroenwest, a big dealership in west london, had never heard of Hydraflush. As far as he was concerned, LHM was something you topped up, as opposed to change. He did have a story about someone with a newish C5 that had been topped up with LHM - apparently it uses a different fluid and LHM knackers the system ...

My understanding is that Hydraflush was originally developed by Pleiades and later given the Citroen seal of approval for hydraulic system flushing and renamed Hydraurincage. I think Total produce it and maybe others.

Regarding old LHM the only way to fully rejuvenate it would be to vacuum distill it and then add whatever additive package Citroen recommend - not within the capabilities of the average DIYer (unless you are a moonshine distiller!).

The colour change of LHM from bright green to almost black is due to the gradual accumulation of sub micronic sized metal and rubber particles as the many sliding hydraulic components slowly wear. There may also be a bit of thermal degradation leading to a darker colour and an increase in viscosity. Also the LHM reservoir breathes to atmosphere as the level fluctuates and may pick up atmospheric contaminants eg dust.

My advice would be to take the old LHM to your local recycling centre and always refill with fresh LHM - you know it makes sense!

Ken

This post has been edited by kenhall1202 on May 10, 2010 01:52 pm

I know someone who used to get rid of waste engine oil and LHM into the fuel tank on a 2.1TD XM.

The car is still going strong with 200k + miles on it.

David.

That's real recycling! Thanks Chaps

J

The beast lives on its own blood! Creepy....

Simple diesel engines are not too fussy about what they get fed. The legal and environmental aspects are a different story.

I've certainly fed old autobox oil (DexII) to my wife's ZX without complaint and can't see LHM being any different. I haven't yet tried it on used engine oil but I'm a great believer in recycling.

I'm a believer in recycling as well. However the effects of long term use of waste mineral oil in modern diesel engines in our vehicles is unclear and I always hand in my waste oil at my filling station for industrial use.

i ran the 2.1 on old lhm, auto fluid, engine oil and rapeseed oil....


do not use engine oil if it has 'flush' in it or its really used, it will clog the fuel filter.


i used to flush my 2.1 engine 5 times at each oil change, the oil i flushed with i used as fuel, so the flushing was free, infact sometimes the cheap oil i used for flushing, ie any tesco/asda oil 10/40, was often cheaper than diesel!

only applies to bosch mecahnical 2.1's