🚗 Classic Fault — Mercedes-Benz W115 (1968–1976)
Air lock in cooling system after hose work
💰 Estimated Repair Cost
Up to $5 USD
Parts and labour estimate
🔧 Tools Required
Drain pan
📋 Overview
After any cooling system work on the W115, air locks can form that prevent proper coolant circulation. The engine overheats locally despite adequate coolant level.
🩺 Symptoms
- Overheating shortly after cooling system work
- hot and cold spots in hoses
- heater blowing cold then hot
🔍 Possible Causes
- Air trapped in cooling system
- incorrect bleed procedure
🛠️ Diagnosis Steps
With engine cold, remove top hose at radiator. Fill system until coolant flows from connection. Refit hose. Idle with heater on full until thermostat opens.
✅ Most Confirmed Fix
Bleed system correctly with heater on during bleeding.
89% of users confirm this fix worked (38 reports)
🔗 Other Mercedes-Benz W115 Faults
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