LHM Leak

Chris570 · Post by **Chris570** » 18 Dec 2009, 16:18

i've got a 94 1.9td SX Xantia.

been fine on LHM for about 10-12k (how long i've had the car) but in the first bit of cold weather we had i had a flickering stop light on. Brakes and steering were all fine and it wasnt constant so i put it down to some ice causing the issue. I pulled up and put the suspension into high and checked the level, the float wasnt even moving, way way down. 0.5l of LHM topped it up to where it should be and i've checked it once a day since then (3 days) and the level has dropped about 2mm on the indicator (no warning lights though).

Now all the hydraulics seem to be working fine, when you move the lever from normal to high it pumps straight away, coming down it pauses for about 20 seconds before doing it (presume that's normal). the brakes are fine and so is the steering so i presume that there is a leak on the low pressure side of things. any pointers of common places to look and how to fix this?

Many thanks guys

HDI · Post by **HDI** » 18 Dec 2009, 16:38

In cold weather the volume of oil reduces due to contraction. That can cause a slightly lower reading on the float. Also , the level sensor can flash because the oil is more viscous and the float reacts more slowly.

Unless you can see visible leaks or drips on the drive anywhere I wouldn't worry.

DickieG · Post by **DickieG** » 18 Dec 2009, 16:44

If the LHM level drops but you can't see any visible signs of leakage then the most logical answer is to suspect a ruptured sphere seal or very low pressure within a sphere allowing the sphere to fill with LHM more than usual, hence the low level in the tank.

RoyChristie · Post by **RoyChristie** » 18 Dec 2009, 16:46

I would be looking under the car for leaks..
can't find any?
have the spheres checked as it sounds like they may be getting a bit flat,
Then there would be relatively more LHM required in the system and less required to pump up the suspension.
This would lead to a low reading on the LHM tank

edit, beaten to that one, agreeing with diagnosis

HDI · Post by **HDI** » 18 Dec 2009, 17:10

The issue started with the cold weather though.

Post by **Peter.N.** » 18 Dec 2009, 17:19

The viscosity of the fluid increases when its cold so it can take longer for the pressure to come up.

All of mine leak, I just top them up from time to time, much cheaper than trying to find/repair leaks

Peter

Old-Guy · Post by **Old-Guy** » 18 Dec 2009, 17:45

The fact that you've had to put in 0.5L makes it clear that you've got a slight leak somewhere. If it's not dripping onto the ground in your regular parking place, then the leak is probably in the engine bay where the undertray is catching it.

When you get a chance, support the car, whip the undertray off and check for a green oily patch. I wouldn't be surprised if the hydraulic pump is leaking slightly - mine does. I'm not going to worry about it until the leakage gets serious.

I'd suggest that if you actually do the weekly check of coolant, oil, and LHM levels you'll soon know if there's a problem to worry about.

citroenxm · Post by **citroenxm** » 18 Dec 2009, 18:01

Peter.N. wrote:
All of mine leak, I just top them up from time to time, much cheaper than trying to find/repair leaks

Peter

None of mine leak, when they do they get fixed! Much cheaper then this LHM thats sooooooooooooooooooo expensive!

Paul

Chris570 · Post by **Chris570** » 18 Dec 2009, 18:01

Cheers for the response guys.

yeah there is a petrol looking stain where i park the car. I don't have an undertray on mine (the other SX i have doesnt either... 2 lazy mechanics i suspect then) but the leak is from the front of the car

another thing i've noticed, the suspension seems to be harder now than it was. The front of the car is easy to push down the rear less so, i presume that points to rear spheres needing changing?

HDI · Post by **HDI** » 18 Dec 2009, 18:01

Apart from when the pipe bursts on mine there are no leaks at all !! There is just a misting around the pipe connection block on top of the LHM tank.

Post by **Peter.N.** » 18 Dec 2009, 18:10

citroenxm wrote:
Peter.N. wrote:

All of mine leak, I just top them up from time to time, much cheaper than trying to find/repair leaks

Peter
None of mine leak, when they do they get fixed! Much cheaper then this LHM thats sooooooooooooooooooo expensive!

Paul

Depends what you value your time at Paul

A litre of fluid every two or three months only works out at about 50p per week.

citroenxm · Post by **citroenxm** » 18 Dec 2009, 18:31

Hmmmm... depends how much you pay for your LHM, but £5 a litre is as bad as Petrol! Or even Diesel

Paul

Post by **Peter.N.** » 18 Dec 2009, 18:43

I can very rarely find where the fluid is coming from and have spent a considerable ammount of time trying, so the way of least resistance is to put some fluid in. It also helps stop your chassis going rusty.

Peter

addo · Post by **addo** » 18 Dec 2009, 21:44

A sphere commonly holds about 400ml with no diaphragm.

Our OP added just over 400ml. He also commented that the suspension feels harder than it used to.

Where's Sherlock?

Chris570 · Post by **Chris570** » 19 Dec 2009, 00:07

i like your thinking, but if a sphere would have blown wouldnt that make at least one corner uncompressible?

does the cold make the suspension harder? (my thinking is the nitrogen losing volume)