Citroen Grand C4 Picasso Ring Gear

Grinding on start, the starter spinning without engaging, and a crunch as the pinion meets a damaged tooth. The diagnostic detail is intermittency: if it only happens sometimes, the wear is confined to one section of the ring, and whether you get a clean start depends on where the engine happened to stop. That pattern is close to conclusive.

On the older Citroens, where the ring is heat-shrunk onto the flywheel, a machinist can press the old one off and shrink a new one on — established work, and cheaper than a flywheel. On a modern dual-mass flywheel that route does not exist and the whole assembly is replaced. Which applies to you depends on the engine, so send the code and we will tell you before you order.

It depends entirely on whether you are buying a bare ring or a complete flywheel. Ask through our form with the engine code and we will price both — and be aware that a good used flywheel with a sound ring gear frequently comes in below a new ring plus the machining labour to fit it, which surprises most owners.

Either the pinion is meshing with damaged ring gear teeth, or the Bendix spring in the starter has weakened and is letting the pinion stay extended after the engine fires. Those are different repairs with different costs, and you cannot tell them apart by ear. Pull the starter and inspect both the pinion teeth and the ring through the aperture before ordering anything.

In almost every case, yes — because the starter is usually what caused the damage. A worn Bendix or a sluggish solenoid hammers the pinion into the ring instead of engaging it smoothly, and fitting a fresh ring gear behind that same starter simply restarts the process. Since getting to the ring gear means removing the gearbox, doing it twice is an expensive way to save on a starter.