🚗 Classic Fault — MG GHN/GHD (1962–1980)
MGB B-series engine oil leak from rear main seal
💰 Estimated Repair Cost
$40 – $200 GBP
Parts and labour estimate
🔧 Tools Required
Engine partial removal, seal tools
📋 Overview
The BMC B-series engine uses a rope rear main seal that weeps oil chronically. A known and accepted characteristic.
🩺 Symptoms
- Oil dripping from rear of engine
- oil on gearbox bellhousing
- oil consumption
- clutch slip
🔍 Possible Causes
- Worn rope rear main seal
- overpressure from blocked breather
- worn crankshaft
🛠️ Diagnosis Steps
Check PCV breather first. Rope seals weep on most high-mileage B-series — lip seal conversion is the permanent fix.
✅ Most Confirmed Fix
Lip seal conversion kit replacement
78% of users confirm this fix worked (28 reports)
🔗 Other MG GHN/GHD Faults
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