Engine Valve Cover Gasket Set Guide for the 1971-1977 Mercury Comet
Stop oil leaks and keep your classic Comet's engine bay clean with the right valve cover gasket.
- You must identify your Comet's engine (inline-6 or 302 V8) before ordering, as the gaskets are engine-specific.
- Modern rubber or silicone aftermarket gaskets from brands like Fel-Pro are a significant upgrade in durability over original cork gaskets.
- The most common cause of a leak after replacement is over-tightening the valve cover bolts, which can warp the cover or crush the new gasket.
- This is a very DIY-friendly repair that requires basic tools and can prevent larger issues like low oil levels and engine misfires.
Why Valve Cover Gaskets Fail on a Classic Comet
After 50+ years of heat cycles, the original valve cover gaskets on a 1971-1977 Mercury Comet are almost always at the end of their life. Originally, many were made of cork, which dries out, becomes brittle, and cracks over time. This leads to oil leaks that can make a mess of your engine, cause a burning smell, and lead to low oil levels. Another common issue is over-tightening the valve cover bolts. This can warp the stamped steel valve covers and crush the gasket, creating a new leak even with a fresh part.
Symptoms of a Bad Valve Cover Gasket
The signs of a failing valve cover gasket are usually easy to spot. Look for these common symptoms:
- Burning Oil Smell: This is the most common sign. Oil leaks from the gasket and drips onto the hot exhaust manifold, where it burns off and creates a distinct, unpleasant smell.
- Visible Oil Leaks: You will see wet, oily residue or grime collecting on the valve cover, cylinder head, and surrounding engine parts. You may also find small oil drips on the ground.
- Low Engine Oil: A persistent leak will cause your engine's oil level to drop over time, which can lead to serious engine damage if not addressed.
- Engine Misfires: In severe cases, oil can leak into the spark plug tubes, fouling the spark plugs and causing the engine to misfire.
⚠️ Identify Your Engine First!
The 1971-1977 Mercury Comet was offered with several engines, including inline-six cylinders (like the 200 and 250 cid) and the 302 cid V8. The valve cover gaskets are different for each engine type. Always confirm your engine size before purchasing a new gasket set to ensure you get the correct part.
Choosing the Right Aftermarket Gasket
For a vehicle of this age, original "OEM" gaskets are no longer available. The good news is that modern aftermarket gaskets are often superior to the original factory parts. They come in different materials, each with its own benefits.
Gasket Material: Cork vs. Rubber vs. Silicone
- Cork: This is the traditional material. It's inexpensive and can conform well to slightly uneven surfaces. However, it's a one-time-use gasket and can dry out and crack over time. It's a decent choice for a budget-friendly, stock application.
- Rubber/Neoprene: Modern rubber gaskets are a significant upgrade. They last longer, are less prone to cracking, and are often reusable if you need to adjust your valves. Brands like Fel-Pro are well-known for their high-quality rubber gaskets.
- Silicone/Performance: High-performance gaskets, often made from silicone, are the top tier. Brands like Cometic and Edelbrock offer these for superior sealing, temperature resistance, and reusability. They are an excellent choice for modified engines or if you want the best possible seal.
Brand Tiers for Your Comet
- Premium (Best Seal): Cometic Gasket, Edelbrock. These brands focus on high-performance applications. Their gaskets are designed for maximum durability and reusability, making them a great investment for a performance-built engine.
- Standard (Reliable Choice): Fel-Pro, Victor Reinz. Fel-Pro is a highly trusted name in the gasket industry and a go-to for most mechanics. Their standard rubber or cork-rubber composite gaskets offer excellent, reliable sealing for a daily driver or stock restoration.
- Value (Budget-Friendly): Apex, Mr. Gasket. These brands provide functional, affordable options. Mr. Gasket is popular in the classic car community, but be aware that some of their kits may use basic cork gaskets that require more careful installation.
Installation Pro-Tip
When installing your new gaskets, do not over-tighten the valve cover bolts! This is the most common mistake. Tighten them just enough to be snug, following a crisscross pattern. Using a 1/4-inch drive ratchet can help prevent applying too much torque. For cork gaskets, a thin layer of gasket sealant on the valve cover side can help hold it in place during installation.
Estimated Replacement Costs
| Part or Service | Estimated Cost |
|---|---|
| New Aftermarket Gasket Set | $17 - $72 |
| Shop Labor | $100 - $180 |
| Shop Total (Parts & Labor) | $117 - $252 |
| DIY Total (Parts Only) | $17 - $72 |
Frequently Asked Questions
Do I need to use sealant with my new gasket?
It depends on the gasket type. High-quality rubber or silicone gaskets are often designed to be installed dry. Cork gaskets may benefit from a light coat of high-tack sealant on the valve cover side to hold them in place. Always check the manufacturer's instructions included with your new gasket set.
What's better for my Comet, a cork or rubber gasket?
For most owners, a modern rubber gasket is the better choice. It offers a longer service life and better durability than traditional cork. Cork can be a good budget option and is forgiving on slightly warped surfaces, but it will not last as long.
Are there any recalls for the valve cover gasket on a 1971-1977 Comet?
No, there are no recalls or technical service bulletins (TSBs) from the National Highway Traffic Safety Administration (NHTSA) related to the engine valve cover gaskets for this vehicle. Any failure today is due to the age and natural wear of the original part.
Is replacing the valve cover gaskets a good DIY job?
Yes, this is an excellent job for a beginner or intermediate DIY mechanic. It requires basic hand tools, is easily accessible on top of the engine, and can typically be completed in about an hour. Just be careful not to over-tighten the bolts on reassembly.
Technical Specifications
OEM Part Numbers: C0DE6584B C0DZ6584B C9DE6584A D0DZ6584A E3BZ6584A
Fitment depends on the engine installed in the vehicle. The 1971-1977 Comet was available with multiple inline-6 engines (170, 200, 250 cid) and a 302 cid V8. Each requires a specific gasket set. Gaskets are commonly made from cork, rubber (neoprene), or silicone.
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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.