When an R107 will not crank, the starter gets blamed first, but the problem is often a cable, a connection, or the neutral safety switch. Here is how I narrow it down.
Where the starter is
It sits low on the engine, at the rear on one side of the bellhousing, with heat from the exhaust nearby. It is reached from underneath with the car safely on stands; on some models steering parts or exhaust brackets are in the way.
Click vs no click
- Single click, no crank: low battery, poor battery cable connection, or worn starter solenoid contacts.
- Rapid clicking: battery low or a bad connection somewhere in the main cables.
- No click at all: neutral safety switch, ignition switch, a broken wire to the solenoid, or a failed solenoid.
- Starter spins but engine does not crank: drive gear (Bendix) problem.
Neutral safety switch
On automatic cars, the starter only works in Park or Neutral. If it starts in Neutral but not Park, or only after jiggling the selector, the switch on the transmission or its linkage adjustment is the likely cause.
Heat soak
A starter that cranks slowly or not at all when the engine is hot, and fine when cold, is often heat soaked: the windings and solenoid lose efficiency when hot. Heat shields, a good ground strap and a healthy battery help. A rebuilt or high-torque replacement usually cures it.
Testing steps
- Battery: at least 12.4 V at rest, above 10 V while cranking.
- Clean and tighten battery terminals and the ground strap to the body and engine.
- Check voltage at the solenoid’s small terminal while a helper turns the key.
- Check the main cable connection on the starter.
Replacement steps
- Disconnect the battery.
- Raise and support the car.
- Remove the cables, then the mounting bolts.
- Lower the starter out, sometimes after moving a steering or exhaust component.
- Install in reverse; clean the mounting surface for a good ground.
Rebuild vs new
A rebuild by a local starter shop can be good value. Quality new or remanufactured units are also widely available. A high-torque gear-reduction starter can help with heat soak.
Related reading
Quick answers
- Is it the starter or the battery? If the lights dim heavily when you turn the key, suspect the battery or cables. If the lights stay bright and nothing happens, look at the switch, neutral safety switch and solenoid circuit.
- Can I tap the starter to make it work? A light tap sometimes frees worn solenoid contacts and gets you home, but it means the starter needs attention soon.
- How long does replacement take? Typically one to two hours with the car on stands, more if steering or exhaust parts are in the way.
