Yes, rear main sealers (like BlueDevil Rear Main Sealer or Bar’s Leaks Rear Main Seal Repair) can work as a temporary or short-term fix for small leaks in the rear main seal. They are designed to condition and swell the rubber seals, helping to stop or reduce leaks without dismantling the engine.
How Rear Main Sealers Work
- Rear main sealers contain special additives and seal conditioners that restore flexibility to old, dry, or shrunken seals.
- As the seal regains its flexibility, it can expand slightly and close small gaps that were causing the oil to leak.
- These products are poured into the engine oil and work over time (typically after driving 100–200 miles) to stop the leak.
When Rear Main Sealers Work Best
- Small leaks due to age-related wear or seal shrinkage.
- When you want a temporary solution or are not ready for an expensive repair.
- As preventive maintenance to keep seals supple and healthy in older engines.
When Rear Main Sealers Might Not Work
- If the rear main seal is severely damaged, torn, or the crankshaft has grooves, the sealer won’t fix it.
- For large leaks or leaks caused by worn engine components, the only solution is usually to replace the rear main seal, which often requires removing the transmission.
Popular Rear Main Sealers
- BlueDevil Rear Main Sealer
- Bar’s Leaks Rear Main Seal Repair
- ATP AT-205 Re-Seal (multi-purpose seal conditioner)
FAQs About Rear Main Sealers
1. Is a rear main sealer a permanent fix?
- No, it’s typically a temporary solution. For a permanent fix, the seal usually needs to be replaced.
2. How long does rear main sealer last?
- It can last for months or years, depending on the condition of the seal, engine maintenance, and driving habits.
3. Can rear main sealers damage my engine?
- Quality products are safe when used as directed. They don’t clog oil passages, but overusing additives in general is not recommended.
Final Answer
Yes, rear main sealers do work for small leaks and can be a cost-effective temporary fix. However, they are not a guaranteed or permanent solution for severe leaks. For lasting repairs, replacing the rear main seal is the best option.
