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1963 MG MGB Problems: 1 Known Issue

1963 model year · NHTSA recalls, manufacturer TSBs, and owner forum reports · Updated August 2026

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Issue summary

According to Au7o's research across NHTSA recalls, manufacturer TSBs, and owner forum reports, the 1963 MG MGB has 1 documented issue. None of the listed issues is rated critical; this is not a complete reliability assessment. Across all issues with published estimates, repair costs range from $200 to $1,800. DIY maintenance guides at au7o.io.

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All 1 Known Issue

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On the 1962-1964 MG MGB 1800 B-series I4 (3-bearing), early MGBs (1962 to early 1964) use the three-main-bearing 18G/18GA B-series. Its crankshaft has a flange at the rear that physically prevents fitting a modern lip seal, so the factory sealed the rear main with a 'reverse scroll' — a machined thread that pumps oil back toward the sump instead of an actual seal. It works only while the scroll and its mating surface are sharp. After decades the crank wears a faint groove and the scroll loses its pumping action, so a few drops always get past, drip out the bellhousing breather hole (which the factory drilled deliberately, knowing it would seep), and mark the driveway. It is not a catastrophic failure, but restorers chasing an oil-tight engine and a clean clutch are constantly frustrated by it.

Common Symptoms

  • Persistent oil drips from the bellhousing/clutch area
  • Oil mist and film on the underside near the flywheel
  • Slow loss of oil with no obvious gasket leak
  • Oil-fouled clutch / clutch slip on high-mile early cars

How to Fix

Accept that a stock 3-main will always seep slightly and manage it: fresh scroll-area surface, correct end-float, a good rear scroll, and keep the bellhousing drain hole open so oil never backs up into the clutch. The proven bulletproofing route during a rebuild is to convert the rear of the crank to take a real lip seal — machine a seal journal/sleeve onto the crank flange and fit a modern lip-seal carrier (kits exist for this) — which finally makes the 3-main oil-tight. Many restorers instead swap to the later five-main-bearing crank/block, which uses a proper lip seal and is the simplest permanent cure. Always renew the front and side cover gaskets and the tappet-chest seals at the same time, as those mimic 'rear main' leaks.

Typical repair cost:$200 - $1,800

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Frequently Asked Questions

What are the most common MG MGB problems?

According to Au7o's research across NHTSA recalls, manufacturer TSBs, and owner forum reports, the 1963 MG MGB has 1 documented issue. The documented issue is: Three-Main-Bearing Rear 'Scroll Seal' Always Weeps Oil. None are rated critical, but regular maintenance is recommended.

Is the MG MGB reliable?

The 1963 MG MGB has 1 known issue compiled from NHTSA recalls, manufacturer TSBs, and owner forum reports. None of the matching records is rated critical; this is not a complete reliability assessment. Regular maintenance following the manufacturer's schedule helps prevent many common problems.

How much does it cost to fix common MG MGB problems?

Repair costs for known MG MGB issues range from $200 to $1,800, depending on the specific problem and whether you choose DIY or professional repair. Au7o provides step-by-step DIY maintenance guides that can help reduce repair costs.

What is the 1962-1964 MG MGB Three-Main-Bearing Rear 'Scroll Seal' Always Weeps Oil?

Early MGBs (1962 to early 1964) use the three-main-bearing 18G/18GA B-series. Its crankshaft has a flange at the rear that physically prevents fitting a modern lip seal, so the factory sealed the rear main with a 'reverse scroll' — a machined thread that pumps oil back toward the… Repairs typically run $200-$1,800. Severity: medium.

Content on this page was compiled with AI assistance using NHTSA complaints, TSBs, owner reports, and public automotive data. While we strive for accuracy, this information may contain errors. Always verify repair procedures and specifications with your vehicle's service manual or a qualified mechanic.

Data compiled from NHTSA recalls, manufacturer TSBs, automotive forums, and AI-assisted research. No aggregated owner-report counts available for this vehicle yet.