When a rear main seal gasket starts to fail, oil leaks can threaten engine longevity and cleanliness. This article highlights five reliable rear main seal gasket kits and covers to help you choose the right one for your GM V8, LS family, or similar engines. The selections target common leak points, ease of installation, and compatibility with 4.8L–6.2L V8 engines. Whether you’re a DIY enthusiast or a professional mechanic, these options balance durability, fit, and value. The buyer’s table below compares the five featured products at a glance.
| Product | Brand | Engine / Application | Includes | Why pick it |
|---|---|---|---|---|
| Dorman 635-518 Engine Rear Main Seal Cover | Dorman | GM V8 LS family; 1999+ 4.8–6.2L | Gasket, bolts, updated seal | Direct OEM-style replacement with durable die-cast aluminum timing cover |
| LS Rear Main Seal Cover & Gasket Bolts | Armker | LS1/LS2/LS3/LM7/LT engines | 1x rear main seal cover, 1x gasket, 12x bolts | Strong compatibility across LS engines; solid cast aluminum for heat resistance |
| Sumyola Rear Main Seal Gasket Cover & Bolts | Sumyola | GM LS variants; 1997–2013 engines | Rear cover, gasket, bolts | Comprehensive kit with multiple OEM numbers replaced |
| A-Premium Engine Rear Main Seal Cover Kit | A-Premium | Chevy Silverado/Express and related models; 4.8–6.2L | Cover, gasket, bolts | Extensive vehicle fitment across Silverado/Express and related families |
| AUTOBABA Engine Rear Main Seal Cover Kit | AUTOBABA | Chevrolet, GMC, Cadillac; wide GM V8 family | Cover with gasket, bolts (kit) | Broad compatibility and complete sealing solution |
Dorman 635-518 Engine Rear Main Seal Cover
The Dorman kit is a direct replacement for the factory rear main seal cover, including a new gasket, installation hardware, and an updated seal design for superior leak prevention. The timing cover is constructed from die-cast aluminum for durability and a tight, leak-free fit. This kit is ideal for a straightforward, complete repair when re-sealing the rear main area is required. Best for: DIYers seeking an all-in-one, factory-accurate replacement with easier installation and durable materials. Limitation: early-models with unique timing configurations may require additional tools not included in the kit.
LS Rear Main Seal Cover & Gasket Bolts
Armker’s kit targets LS-based engines (LS1/LS2/LS3/LM7/LQ4/LQ9, 4.8L–6.2L, 1997–2013). It includes a rear main seal cover and a gasket with 12 bolts for a complete seal. Best for: LS-powered builds and repairs where a full cover and bolt kit can simplify the repair and ensure a leak-proof seal. Better for: vehicles like Silverado, Suburban, Tahoe, Sierra, and Yukon with the LS family. Limitation: compatibility relies on correct engine family; confirm your exact LS variant before purchase.
Sumyola Rear Main Seal Gasket Cover & Bolts
Sumyola’s kit replaces parts 635-518 and 12633579/12639250, designed for a broad array of GM vehicles from 1997–2013. It accommodates Chevrolet, GMC, and Cadillac models such as Silverado, Suburban, Tahoe, Yukon, Sierra, and Escalade. Best for: owners seeking a complete kit that covers multiple OEM part numbers and a wide vehicle range. Caution: verify exact vehicle and engine alignment to ensure fitment; data indicates broad compatibility but not every mid-year variant is guaranteed.
A-Premium Engine Rear Main Seal Cover Kit
A-Premium’s kit is designed for a wide GM footprint, including Chevrolet Avalanche, Silverado, Express, Suburban, Tahoe, Caprice, and more. It’s suitable for 4.8L–6.2L engines and is marketed for multiple model years with extensive fitment. Best for: those working on heavy GM trucks and SUVs, especially when upgrading multiple rear main seal components at once. Choose this if you drive a full-size GM SUV or pickup and want broad coverage. Limitation: very large fitment list may require cross-checking specific year/trim to avoid a mismatch.
AUTOBABA Engine Rear Main Seal Cover Kit
AUTOBABA’s kit targets a broad GM lineup including Escalade, Yukon, Sierra, Suburban, Tahoe, Silverado, and Express. It consolidates a rear main seal cover with gasket and bolts for a single, complete repair. Best for: owners of larger GM SUVs and pickups who want a unified part kit to streamline installation. Caution: check the exact compatibility table for your year and engine family to prevent misfit.
GoaMotors Rear Main Seal Set Oring Gasket Crankshaft Seal
GoaMotors offers a gasket and crankshaft seal set designed for Chevrolet, GMC, Hummer, Pontiac, Isuzu, and more. It emphasizes preventing motor oil leaks around camshafts, rockers, and valves. Best for: repairs focusing on preventing additional leakage around the engine’s rear area and related seals. Limitation: a broad compatibility list can require precise vehicle verification to ensure the correct part match.
Buying Guide: Key Considerations for Rear Main Seal Gasket Kits
- Engine compatibility: Confirm your engine family (GM LS, Vortec, etc.) and year range before selecting a kit.
- Included components: Look for a complete kit with the rear main seal cover, gasket, and bolts to avoid missing pieces.
- Material and durability: Die-cast aluminum and heavy-duty gaskets reduce leak risk and provide a longer-lasting seal.
- Vehicle fitment breadth: Some kits cover many models; others are more targeted. Choose based on your vehicle’s make, model, and year.
- Installation considerations: Some kits assume standard timing covers; verify whether additional tools or modifications are needed for your setup.
- OEM-number compatibility: If you’re replacing OEM 635-518, 12633579, or 12639250 numbers, ensure the kit lists those replacements.
- Warranty and return policy: Check if the seller provides a warranty or return option in case of fitment issues.
Frequently Asked Questions
- What is a rear main seal gasket, and why replace it?
It seals the crankshaft rear where it exits the engine block, preventing oil leaks and maintenance issues. Replacing it helps stop oil loss and keeps the engine compartment clean. - How do I know if my GM LS engine needs the rear main seal kit?
Visible oil leaks at the bell housing area or pooling around the rear of the engine can indicate a needed seal kit replacement. Confirm engine family compatibility first. - Can I install the kit myself, or should a mechanic do it?
A DIY installation is feasible for experienced users with proper tools. Some kits include hardware for a complete seal assembly, which simplifies the process; otherwise, seek professional help for a precise seal. - Do these kits come with all the gaskets I need?
Most kits include the rear main seal cover, gasket, and bolts, but verify the exact contents listed by the seller to avoid missing components. - Will using a kit from a different brand cause issues?
Kits with compatible part numbers and engine family guidelines should fit correctly. Always verify compatibility with your specific year and model. - Are OEM-replacement part numbers important?
Matching OEM numbers like 635-518, 12633579, or 12639250 can help ensure a precise fit. If a kit lists replacements, confirm it aligns with your vehicle’s requirements.