Swirl Motor Failure (3.0 CRD)
SeriousEngineOil leaks from the turbocharger intake pipe can drip directly onto the swirl flap motor located in the "V" of the engine, causing it to short out and put the car into limp mode.
The 300C arrived in the UK in 2005 with the Mercedes OM642 3.0-litre diesel V6 and a 5.7-litre Hemi V8. Early cars had the best equipment but are now the oldest and most likely to show suspension and electrical age-related issues.
Oil leaks from the turbocharger intake pipe can drip directly onto the swirl flap motor located in the "V" of the engine, causing it to short out and put the car into limp mode.
On early 300C diesels, the inlet manifold can corrode internally and suck plastic fragments into the engine, causing potentially catastrophic damage. Cars built between 2005 and 2007 are most affected.
The 300C is a very heavy car, and its suspension components (derived from the Mercedes W211) take a beating on UK roads. Ball joints and control arm bushes often last less than 40,000 miles.
The alternator is prone to premature failure, often caused by diesel fuel dripping onto it from cracking rubber fuel hoses. The earth cable can also corrode, leaving the car unable to start.