Starters face a challenging life in the daily operations of a vehicle: They must quickly and reliably ensure that the combustion engine transitions from a standstill to self-operating. They perform this task even under adverse environmental conditions - whether in winter, under high heat, or, depending on the application, in the presence of high humidity or dust.
Moreover, starters are designed to engage with the toothed ring of the flywheel at the front end. This means they also get exposed to dirt from wear and tear and clutch dust.
All these factors can wear out a starter, but only if it's not designed for such conditions! Depending on the application and operating environment, starters can be built differently to combat dirt ingress. In reality, a starter can get more or less dirty depending on where it's used.
For instance, the starter of a wheel loader in mining operates under completely different conditions than the same type installed in a long-haul truck.
There are three distinct types of starters:
Several issues can cause a starter to fail. Here's what you should know about the causes and effects of dirt accumulation:
Dirt in the freewheel binds the grease in the freewheel clutch. This might make the freewheel so stiff that during the start, the entire starter rotates with the engine. Alternatively, the freewheel clutch may lose power in both directions, causing it to slip. While the starter turns, it doesn't drive the combustion engine.
If the dirt is bound by grease on the shaft, the pinion gear with the freewheel clutch can't smoothly engage or disengage with the toothed ring. Depending on the level of dirt, the solenoid's force might not be sufficient to push the pinion gear into the toothed ring.
Sometimes, the dirt accumulation is so severe that it reaches the engagement lever, partially blocking it. This can prevent the pinion gear from engaging deeply enough.
The result: The contacts in the solenoid do not close, the starter doesn't turn, and the engine doesn't move an inch.
Depending on the amount of dirt in the motor, a layer of grime can form on the collector. This might increase the resistance between the collector and the carbon brushes, reducing the starter's performance.
While starters are protected against splashing water based on their protection class, they can be sensitive to aggressive and oily substances like engine, gearbox, hydraulic oil, or other operational fluids. If these liquids enter the starter in large quantities, it can lead to malfunctions, even total starter failure.
Finally, here are some preventive maintenance tips for your workshop:
When replacing the starter, always thoroughly clean its surroundings. Open connections and openings on the transmission bell housing should be sealed to prevent dirt ingress. Address leaks from the engine or nearby areas immediately! Depending on the area of use, consider occasionally washing the engine with a high-pressure cleaner - but be gentle and maintain an appropriate distance! You don't want to accidentally cause water damage to the starter.