🚗 Classic Fault — Mercedes-Benz W115 (1968–1976)
Ignition coil breaking down when hot
💰 Estimated Repair Cost
$30 – $70 USD
Parts and labour estimate
🔧 Tools Required
Multimeter, heat gun
📋 Overview
The ignition coil develops an internal fault that only appears when hot. The engine runs well cold but begins to misfire badly after 10-15 minutes, then recovers when cold again.
🩺 Symptoms
- Misfiring that develops after engine warms up
- engine dies hot, restarts when cool
- intermittent fault
🔍 Possible Causes
- Failing ignition coil with heat-related breakdown
- poor coil earth connection
- ballast resistor failure
🛠️ Diagnosis Steps
Test spark intensity when fault is present. Swap coil with known good unit. Use heat gun on coil.
✅ Most Confirmed Fix
Replace ignition coil. Check ballast resistor value.
75% of users confirm this fix worked (18 reports)
🏷️ Parts Needed
Bosch ignition coil; ballast resistor
🔗 Other Mercedes-Benz W115 Faults
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