XM

Needless to say, you should always use the correct grade oil in your gearbox. Total manufactures it for Citroën/Peugeot with a grade of 75W. This is sometimes referred to as 'motorcycle gearbox oil'. Substitutes, ATF for instance, or any gearbox oil with incorrect grade, will leak from the top of the box, through the plastic tube where the gearbox lever enters the housing. Even with the correct oil it will leak slightly (it seems that the gearbox was not actually designed to operate in the slanted position it is fitted in).

First of all, shop around for the clutch--the original Citroën ones are very expensive (exceeding 500 EUR), so I actually went to the shop and opened up a clutch kit. It turned out it had parts from Valeo and Sachs (I have been told some also have Luk parts). I looked up the suppliers, and found an XM kit from Sachs with a three year warranty. When I checked it out it turned out to be exactly the same kit down to the Valeo parts. The only difference was that it cost less than half the price.

The easiest way to change the clutch is actually to have the whole engine out.

With the roadwheel still in place, remove the wheel nut securing pin and the crown, then loosen the wheel nut (the one on the CV joint) about a quarter of a turn or so, just enough to get it going. Applying the park brake or even the foot brake (assuming the system is still under pressure) will help. Loosen the wheel bolts slightly, then release the park brake.

There are several cabin temperature control systems fitted to the various models.

What is "Climate Control" (on a P reg, 1996 XM TD 2.5) as opposed to Air Conditioning?

There were several 'climate control' systems fitted to the XM. In fact, IIRC the manual refers to them all as 'climate control'. Onseries 1 there was:

1) Manual
2) Semi-auto (looks very similar to manual)
3) Full auto

1.5) Later series 1 also came with manual but separate for driver and passenger side.

You can delay the corrosion if you use stainless steel exhaust components. For instance, Walker, a widely known aftermarket manufacturer of exhaust parts has a family named Aluminox. These parts are made of stainless steel and covered by a layer of aluminum alloy. The estimated life of these exhaust components exceeds five years under normal use while their price is only about 30% higher than that of the standard components. The last time I asked it was only available for the diesel models.

Citroën used various systems of two manufacturers, Bosch and Magneti Marelli. All those systems operate on very similar principles so troubleshooting them involves more or less the same steps.

There are two basic categories: fuel injection (EFI) and engine management (EMS). EFI systems, as their name implies, are responsible for the injection of fuel only, the ignition sparks are created using traditional methods (a breakerless distributor). EMS systems, in contrast, govern both fuel injection and ignition themselves.

Traditionally, stroboscopes were built with xenon flashlights such as those used in photographic flashguns. However, these flashlights require a 400-600 V voltage and even more for igniting them. Needless to say, electric shocks of such voltages are often lethal. Unless you have experience in building such high voltage circuits (including proper insulation) and also have measuring equipment to help with the process, you shouldn't even think of building one.

It usually dies either when you (try to) start the engine or when you stop it, rarely while it's running. The engine will not start because it will not be getting any fuel. The reason is usually overheating and deformations in the coil whichresult in the valve plunger getting stuck, or internal shorts or open circuits (due to heat) in the coil.

Clean combustion resulting in clean oil (assuming it has the proper grade, not some cheap concoction) is essential not only for the engine but for the turbo as well. Most people are not aware that a turbo can be--and actually should be--cleaned every 150,000 km or so. This procedure will make it last forever.

Most people are not aware that the main reason a diesel engine wears out is improper combustion, usually caused by worn out injectors, improper timing, or simply lack of air (influenced by several factors, one of which may simply be a dirty air filter). Anything which produces soot (eg. particulates), including the "black smoke" effect, results in particulates ending up in the engine oil. This soot then accumulates in areas where oil flow is low, like behind the piston rings. As the deposits grow, the ring is being forced outwards.