Starter solenoid: replacement and selection

When and why it is necessary to replace starter solenoid

Manufacturers do not specify exact lifetime of the starter solenoid. Replacement of the part is performed in case of thermal damage of the contact plates or power contacts, burning-out or tearing of the winding, breakdown of drive elements (mechanical damages of the armature, jamming or loosening of the spring), damaging of the magnet due to casing integrity violation, oxidation of the rod.

Wear-out of the drive elements is caused by frequent use and improper usage of the starter. The contacts and winding are often damaged as a result of short circuit due to ingress of moisture or voltage variations in the car electric circuit. A road accident can become the cause for magnet damaging. And the component rod gets oxidized because of ingress of condensed moisture at temperature variations.

The main sign of solenoid starter switch defect is unstable operation of the starter, during which the engine is not starting, but clicks of starter solenoid at ignition key turning are heard. This is a symptom of thermal damaging of the contact plates. Jamming of drive elements or winding breakage can be indicated by the solenoid non-actuation (absence of specific click at ignition turning on). Also defectiveness of the starter solenoid often shows itself in free rotation of the starter after engine start. Buzzing is heard during this.

Replacement of the part is performed with the help of a lifting device, as the starter is often hard-to-reach: removal of many mechanisms will be required. You need to de-energize the car before replacement of the part, as any actions related to the starter are prohibited with energized electric system. This is dangerous for human health, and can lead to short-circuit of the whole car wiring.

How to select starter solenoid

The contacts of starter solenoids can be made of various materials. Copper is used for it more often, and brass – rarely. The relays with copper contacts have better current conductivity, while the ones with brass contacts are more affordable by price.

High-quality and durable products are offered by various manufacturers. Among them are such famous brands as Magneti Marelli, Bosch, Meat & Doria, Spare Parts.

The starter solenoids differ from one another by size, construction, type of fastening to the starter, and rod shape. Also power contacts can be mounted vertically or horizontally, while the distance between them varies according to vehicle technological features.