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MGB oil seal leaking ?
- Thread starter whiteMGB
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thojr
Freshman Member
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If you’re still seeing a small leak after replacing the oil pan gasket, it could be the main seal. There’s a product called AT-205 Re-Seal that works on engines, transmissions, and differentials. Curious if anyone’s used it on an MGB and how well it works—especially for the main seal
Welcome to the club! If there’s no oil under an MGB, there’s usually no oil in it.
Regarding AT-205, it is a polymer-based plasticizer that works by softening and swelling rubber seals. While it can be effective for modern rubber seals that have hardened over time, the MGB rear main seal is a bit of a different beast. If your leak is actually coming from the rear main, keep in mind that many of these older designs rely on a scroll seal or cork, which won't respond to chemical "re-sealers" the same way a modern viton seal would.
Most of the veterans here will tell you that those "stop leak" products are often just a temporary band-aid. Before pouring anything in, make sure it’s not just the rocker cover gasket or the oil pressure sensor line leaking down the back of the block—it’s very common for those to mimic a main seal leak!
Regarding AT-205, it is a polymer-based plasticizer that works by softening and swelling rubber seals. While it can be effective for modern rubber seals that have hardened over time, the MGB rear main seal is a bit of a different beast. If your leak is actually coming from the rear main, keep in mind that many of these older designs rely on a scroll seal or cork, which won't respond to chemical "re-sealers" the same way a modern viton seal would.
Most of the veterans here will tell you that those "stop leak" products are often just a temporary band-aid. Before pouring anything in, make sure it’s not just the rocker cover gasket or the oil pressure sensor line leaking down the back of the block—it’s very common for those to mimic a main seal leak!