What causes weak starter motor when the engine is hot?
2 Answers
After the engine cools down, restart it. If the starter motor operates normally, it indicates an issue with the electromagnetic switch, which should be replaced. Check if the battery is low on charge. If the battery is in good condition, inspect the starting circuit. If the circuit is also fine, then the problem lies with the starter motor, and it should be replaced directly. Examine the coolant temperature sensor and the intake air temperature sensor. If their resistance values do not meet the standard, they should be replaced. Below is relevant information: Check the air flow meter: Inspect the air flow meter or the intake manifold absolute pressure sensor. Use a multimeter or specialized equipment to measure the signal voltage of the air flow meter or the intake manifold absolute pressure sensor. If the readings do not meet the requirements, they should be replaced. Starter motor: The starter motor is an electric motor or engine that rotates by the force exerted on an energized coil in a magnetic field, driving the starter rotor to spin. The small gear on the rotor drives the engine flywheel to rotate, which is the working principle of the starter motor, also known as the starter. With technological advancements, starters have adopted electronic modes. Electronic starters have replaced the cumbersome hand crank, making car driving more convenient and faster.
I've encountered the issue of weak starter motor performance during hot starts several times. The main reason is that the battery's performance degrades in high-temperature environments, especially in summer. Old batteries experience increased internal resistance and weakened discharge capacity, leading to lower starter motor speed. Additionally, the starter motor itself may overheat. If the housing accumulates dust or has poor heat dissipation, the motor coils will heat up and reduce torque output. Corroded or loose cable connections can worsen due to thermal expansion, resulting in poor current conduction. Once when my car was parked under scorching sunlight, it made clicking noises during startup. Upon inspection, I found the battery terminals were completely covered with oxidation layers, and the situation improved significantly after cleaning. I recommend first testing the battery voltage - if it's below 12 volts, it's time for a replacement. Also, check the starter motor's connection points and tighten the nuts. Regular maintenance can prevent this problem, so don't wait until you're stranded on the road to regret it.
