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- £48.70
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Description
xDirect-fit replacement for Gen 3 LS engines
The Michigan Motorsports Gen 3 LS Valley Cover Gasket is designed to replace GM part 12558178 with a modern, durable seal. Made from molded rubber with an integrated sealing bead, it creates a consistent oil seal between the valley cover and the engine block across 1997–2007 Gen III LS platforms. This gasket is built to perform under the heat and vibration common in daily driving and performance applications.
Key design features
- Precision molded rubber with an integrated sealing bead for reliable sealing.
- OEM-grade replacement that matches or exceeds factory specifications for stock and performance builds.
- Direct replacement for GM 12558178, ensuring a familiar fit during maintenance or rebuilds.
- Designed to resist oil exposure, heat, and vibration over the long term.
- Compatible with a wide range of LS Gen 3 blocks, including iron and aluminum variants.
Ideal uses and real-world scenarios
- Camshaft installations where a reseal is recommended to prevent leaks during upgrades.
- Valley cover upgrades or gasket replacements as part of an engine reseal or rebuild.
- Maintenance in cars, trucks, and SUVs powered by Gen 3 LS engines in the 1997–2007 era.
Installation tips and notes
Prepare the mating surfaces by cleaning thoroughly and inspecting for damage. Install with even pressure and follow torque specs for valley cover bolts. This gasket is designed for a straightforward swap on compatible engines and aims to reduce rework from oil leaks.
Why choose Michigan Motorsports
Our gasket emphasizes dependable sealing and factory-quality materials without complicating your rebuild. While performance outcomes can vary by overall engine condition and installation quality, this part is built to support reliable operation and easier maintenance in Gen 3 LS builds.
FAQ
Q: Which engines is this gasket compatible with?
A: Fits 1997–2007 Gen 3 LS engines, including LS1, LS6, LM7, LQ4, LQ9, and LR4.
Q: Does this replace GM part 12558178?
A: Yes, it is a direct-fit replacement for GM 12558178 and matches OEM specs.
Shipping & Return
xReturns Policy
You may return most new, unopened items within 30 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).
You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).
If you need to return an item, simply login to your account, view the order using the "Complete Orders" link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.
Shipping
We can ship to virtually any address in the world. Note that there are restrictions on some products, and some products cannot be shipped to international destinations.
When you place an order, we will estimate shipping and delivery dates for you based on the availability of your items and the shipping options you choose. Depending on the shipping provider you choose, shipping date estimates may appear on the shipping quotes page.
Please also note that the shipping rates for many items we sell are weight-based. The weight of any such item can be found on its detail page. To reflect the policies of the shipping companies we use, all weights will be rounded up to the next full pound.
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