1964-1974 Ford Mustang Engine Valve Cover Gasket Replacement Guide
Stop those messy oil leaks and keep your classic Mustang's engine bay looking its best.
- The most common cause of failure is the gasket hardening and cracking from age and heat.
- Do NOT over-tighten the valve cover bolts; this is a primary cause of new leaks.
- Modern rubber or silicone gaskets from brands like Fel-Pro are often a durable upgrade over original cork gaskets, especially for cast aluminum valve covers.
- Thoroughly cleaning the mating surfaces on both the cylinder head and the valve cover is critical for a leak-free seal.
Is Your Mustang Leaking Oil? Check the Valve Cover Gaskets.
An oil leak is one of the most common issues for any classic car, and the first-generation Ford Mustang is no exception. The constant heat from the engine causes the original valve cover gaskets to become hard, brittle, and cracked. This allows oil to seep out and drip onto other engine parts, creating a mess and a potential fire hazard if it drips onto hot exhaust manifolds.
Symptoms of a Failing Valve Cover Gasket
- Visible Oil Leaks: You may see oil residue on the valve cover itself, or dripping down the side of the engine block. On V8 engines, this is common above the spark plugs.
- Burning Oil Smell: If oil leaks onto the hot exhaust manifold, it will burn off, creating a distinct and unpleasant smell while you drive.
- Low Engine Oil: A significant leak can cause your engine oil level to drop over time, requiring frequent top-offs.
- Dirty Engine Bay: Leaking oil attracts dirt and grime, making the area around the valve covers look dark and greasy.
A Common Mistake: Over-tightening
When a leak appears, a common instinct is to tighten the valve cover bolts. This is often a mistake. Over-tightening, especially with cork gaskets, can split the gasket or warp the valve cover, making the leak even worse. The correct torque is very low, typically around 3-5 ft-lbs (or about 40-60 inch-pounds), which is just a little more than hand-tight.
Choosing the Right Aftermarket Gasket
For a 1964-1974 Mustang, you won't be buying a "new OEM" gasket from Ford. The market is all aftermarket, and today's technology often provides a better-than-original solution. The main choice you'll make is the gasket material.
Gasket Material: Cork vs. Rubber vs. Silicone
- Cork: This is the traditional material. It conforms well to imperfections on stamped steel valve covers. However, cork is prone to drying out, cracking, and can be easily damaged by over-tightening. It's a budget-friendly option that works if installed carefully on clean, flat surfaces.
- Cork-Rubber Composite: Brands like Fel-Pro offer a "Blue Stripe" cork-rubber mix that combines the conformability of cork with the improved durability and oil resistance of rubber. This is a solid middle-ground choice.
- Rubber/Silicone: These are the modern, premium options. They are far more durable, resistant to heat and oil, and are often reusable. If you have cast aluminum valve covers or plan to remove your valve covers periodically for adjustments, rubber or silicone gaskets are the best choice. They are less forgiving on warped or damaged stamped steel covers.
Pro Tip: Match the Gasket to Your Valve Cover
For original-style stamped steel valve covers, high-quality cork or cork-rubber gaskets often provide the best seal. For heavier, more rigid cast aluminum aftermarket valve covers, a rubber or silicone gasket is superior.
Aftermarket Brand Tiers
While many brands are available, they generally fall into a few categories based on quality and reputation among Mustang owners.
| Tier | Brands | Description |
|---|---|---|
| Premium / Performance | Cometic Gasket, Edelbrock, Fel-Pro (Performance Line) | These brands offer high-end materials like silicone or steel-core laminates. They are designed for high-performance engines and are often reusable. Cometic and the performance lines from Fel-Pro are highly regarded but come at a higher price. |
| Trusted Aftermarket | Fel-Pro, Victor Reinz, Mr. Gasket | This is the sweet spot for most owners. Fel-Pro is consistently recommended in forums for its quality, fit, and reliability in both cork and rubber materials. Victor Reinz and Mr. Gasket are also solid, widely available choices. |
| Standard / Economy | Apex, various store brands | These are the most affordable gaskets. They will get the job done for a daily driver or a quick fix, but may not have the longevity or advanced features of the higher-tier brands. |
Frequently Asked Questions (FAQ)
Do I need to use sealant (RTV) with my new gaskets?
Most modern rubber and silicone gaskets are designed to be installed dry. However, many mechanics apply a few small dabs of RTV in the corners of the valve cover to hold the gasket in place during installation. It is also common practice to apply a small dab of sealant at the points where the cylinder head meets the intake manifold and timing cover, as these are natural leak points. Always check the gasket manufacturer's instructions.
Is replacing valve cover gaskets a good DIY job?
Yes, for most 1964-1974 Mustangs, this is an excellent job for a beginner. It requires basic hand tools and is usually very accessible, especially on inline-6 and small-block V8 engines. The key is to be patient, thoroughly clean the mating surfaces on both the head and the valve cover, and not to over-tighten the bolts on reinstallation.
Do I have to drain the engine oil to change the gaskets?
No, you do not need to drain the oil. The oil level in the pan is well below the cylinder heads. A small amount of residual oil may be in the valvetrain area, so have some rags ready when you remove the cover.
What is the torque specification for valve cover bolts?
The torque is very low, typically between 3 and 5 ft-lbs (foot-pounds), which is 36 to 60 in-lbs (inch-pounds). This is not very tight at all. The goal is to simply compress the gasket enough to create a seal. Over-tightening is a primary cause of leaks.
Are there any recalls for valve cover gaskets on a 1964-1974 Mustang?
No. There are no active recalls or Technical Service Bulletins (TSBs) from Ford for valve cover gasket issues on this generation of Mustang. Any problems you encounter are due to the age and wear of the original components.
Technical Specifications
Gasket material is the primary specification. Options include cork, rubber, silicone, and cork-rubber composites. The correct gasket depends on the engine (Inline-6, 289/302, 351W, 351C, FE-series V8) and the type of valve cover (stamped steel or cast aluminum).
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The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
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- Is Your Mustang Leaking Oil? Check the Valve Cover Gaskets.
- Symptoms of a Failing Valve Cover Gasket
- A Common Mistake: Over-tightening
- Choosing the Right Aftermarket Gasket
- Gasket Material: Cork vs. Rubber vs. Silicone
- Pro Tip: Match the Gasket to Your Valve Cover
- Aftermarket Brand Tiers
- Frequently Asked Questions (FAQ)
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