1972 CITROEN DS?

It does sound like the suspension fluid, doesn't it?

And the clicking sound sounds like the suspension pump, which should activate 2 times per minute, not every 4 seconds.

Go to:

http://www.classiccars4sale.net/classic-car-how-to...

and note the section: REAR SUSPENSION

It certainly is worth keeping your DS in good running order as these iconic cars can only continue to increase in value.

And, let's face it, it looks like a work of art just sitting there.

Beautiful.

The green fluid is the LHM suspension (and brake!) system fluid. If you have a leak somewhere, the hydraulic pump will have to work harder for your system to remain pressurized. This makes a clicking sound, which you should not hear more than twice a minute. Have it checked by a person who knows what he's doing.The LHM is vital to the suspension and the brake system, so if it leaks, you not only loose grip on the road, you also loose the ability to stop when you need to. So your car goes dangerous!

The hydraulic system usually has a reservoir, a pump (which is driven by the drivebelt, just like the dynamo and waterpump), four green suspension spheres, a fifth collector sphere and a load of copper, aluminium and rubber tubing. All of these component can leak, but the tubes are the most likely. The metal ones rust and the rubber ones dissolve after time.

The LHM fluid is a mineral oil which should be bright green. If it is going brown, you have to replace it. Flushing the system in between changes, by using temporary red LHM helps to prevent problems. Most likely, on an old DS, you will have to replace the fluid every five year. The tubes in general last about 15 to 20 years. So on a 1974 DS, they should have already been replaced at least twice. The spheres contain nitrogen, which permeates through the membrane that separates the gas from the hydraulic fluid. Over time (10 years) the spheres go dead (your car doesn't 'float' anymore, but bounces on short bumps). The spheres can be easily refilled with nitrogen, but if that has been done several times, it is better to replace them (all five!) too.

Indeed, a DS is worth keeping in good knick. It is an old-timer, so as an owner, you should be prepared to spend some hard cash on it the keep enjoying it. A complete overhaul of the hydraulic system would be advisable for a 40 year old car, but it might not be necessary yet.