🚗 Classic Fault — Mercedes-Benz W115 (1968–1976)
Water pump plastic impeller disintegration
💰 Estimated Repair Cost
$60 – $150 USD
Parts and labour estimate
🔧 Tools Required
Basic tools, drain pan
📋 Overview
Some replacement water pumps use plastic impellers that disintegrate with age. When the impeller breaks up, coolant circulation ceases despite the pump appearing to turn, causing overheating with no apparent cause.
🩺 Symptoms
- Sudden overheating
- pump turns but no circulation
- no impeller fragments visible without removal
🔍 Possible Causes
- Disintegrated plastic impeller
- impeller separated from shaft
🛠️ Diagnosis Steps
Remove pump from engine. Inspect impeller visually. Check for play between shaft and impeller.
✅ Most Confirmed Fix
Replace water pump. Specify metal impeller type.
77% of users confirm this fix worked (18 reports)
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