Replacing the Engine Valve Cover Gasket on a 1960-1970 Mercury Comet
A complete guide to stopping those messy oil leaks from the top of your Comet's engine.
- Do not over-tighten the valve cover bolts; the torque spec is very low (3-8 ft-lbs). This is the #1 cause of leaks.
- For stock stamped-steel valve covers, a quality cork gasket is often best. For aftermarket cast aluminum covers, use rubber.
- Before installation, make sure the valve cover's sealing flange is clean and perfectly straight. Hammer it flat if needed.
- Use a tacking sealant to glue the gasket to the valve cover only, which helps hold it in place during assembly.
Is Your Comet Leaking Oil From the Top?
An oil leak from the valve cover gasket is one of the most common issues on a classic car like the 1960-1970 Mercury Comet. The original gaskets were often made of cork, which can dry out, crack, and shrink over decades of heat cycles. This leads to annoying oil drips on your garage floor and a burning oil smell as the oil hits the hot exhaust manifold. Fortunately, this is one of the easiest and most affordable repairs you can do.
Common Failure Symptoms
- Burning Oil Smell: This is the most common sign. Oil leaks from the valve cover, drips onto the hot exhaust manifold below, and burns off, creating a noticeable smell, especially when the engine is warm.
- Visible Oil Leaks: You may see wet, oily residue or fresh oil around the perimeter of the valve covers at the top of the engine. Because it's at the top, the oil can run down the side of the engine block, making it look like other gaskets are leaking.
- Low Engine Oil Level: A significant leak will cause your engine oil level to drop over time, requiring you to top it off frequently.
- Dirty, Grimy Engine: Leaking oil attracts dirt and grime, leaving a thick, greasy mess on the side of your engine.
The #1 Mistake: Over-tightening
The most common mistake when installing valve cover gaskets on these engines is over-tightening the bolts. The original stamped steel valve covers are thin and will bend or warp easily. This creates an uneven surface that no gasket can seal. The bolts only need to be snug, around 3-8 ft-lbs of torque. Many experienced mechanics use a nut driver and just tighten them by hand until they are snug.
Choosing the Right Aftermarket Gasket Set
Original equipment (OEM) gaskets for a car of this age are no longer produced. The aftermarket, however, offers excellent options that are often better than the original. The main choice you'll face is the material: classic cork or modern rubber.
Material Showdown: Cork vs. Rubber
- Cork Gaskets: These are traditional and often made from a cork-and-rubber composite. Their main advantage is their ability to swell slightly and conform to imperfections, which is helpful for the stock stamped-steel valve covers that may not be perfectly flat. However, they are a one-time-use part, can dry out over time, and are easily crushed if you over-tighten the bolts.
- Rubber/Silicone Gaskets: These are more durable, reusable, and resistant to oil and heat. If you plan on removing your valve covers for things like valve adjustments, rubber gaskets are the better choice. The downside is they are less forgiving of warped valve cover flanges. They require a clean, flat surface to seal properly.
Pro Tip: Before you order, check your valve covers. If you have the original, thin stamped-steel covers, inspect the bolt hole flanges. If they are bent or distorted, carefully hammer them flat before installation. For stamped covers, a quality cork gasket from a brand like Fel-Pro is often the most reliable choice. If you have upgraded to thicker, cast aluminum valve covers, a rubber gasket is superior.
Brand Quality Tiers
Not all gaskets are made the same. Here’s a breakdown of the available brands:
- Premium Performance (High-End): Brands like Cometic Gasket and Edelbrock are at the top. They are designed for high-performance applications, often with superior materials that can justify the higher price, especially if you have a modified engine. Cometic is well-regarded in the racing community.
- Excellent Quality (The Go-To Choice): Fel-Pro is the most recommended brand in forums for these engines. They offer high-quality cork and rubber options that are known to fit and seal well. Mr. Gasket is another classic brand with a solid reputation in the hot-rod and classic car world.
- Standard Replacement (Good Value): Brands like Apex, Reinz, and Victor Gaskets offer reliable, OE-quality replacements. They are a good choice for a stock engine and provide excellent value for the price.
| Item | Estimated Cost |
|---|---|
| New Aftermarket Gasket Set | $17 - $72 |
| Shop Labor | $90 - $180 |
| Total Estimated Cost | $107 - $252 |
Frequently Asked Questions (FAQ)
Which is better for my Comet, a cork or rubber gasket?
For original stamped steel valve covers, a high-quality cork gasket (like Fel-Pro's Blue Stripe) is often best because it can better seal minor imperfections in the cover's flange. If you have upgraded to cast aluminum valve covers, a rubber gasket is the more durable and reusable option.
Do I need to use sealant or RTV on the gasket?
You should not use RTV to coat the entire gasket. The best practice is to apply a thin layer of a non-hardening sealant like Permatex High-Tack or 3M weatherstrip adhesive to the valve cover side only. This glues the gasket to the cover, holding it in place during installation. The side that touches the cylinder head should be installed dry to allow for easy removal in the future.
How tight should the valve cover bolts be?
Not very tight at all. The typical torque specification is only 3 to 8 ft-lbs. Over-tightening is the number one cause of leaks as it warps the cover. It's best to use a low-range torque wrench or simply tighten them until they are snug using a small wrench or nut driver, then give them a slight turn more.
Are there any recalls for this part?
No. There are no recalls or technical service bulletins (TSBs) from the NHTSA related to the engine valve cover gaskets for the 1960-1970 Mercury Comet. This is a standard maintenance item.
Why is my new gasket leaking?
The most likely causes are that the valve cover bolts were over-tightened, warping the cover, or the sealing flange on the valve cover itself is bent and not flat. Another possibility is that the surfaces were not cleaned properly before installation. Always check the valve cover for straightness before installing a new gasket.
Technical Specifications
Gaskets are specific to the engine family. The 1960-1970 Comet used several Ford engines, primarily the small inline-six (144, 170, 200, 250 cid) and the small-block V8 (260, 289, 302 cid). Ensure the gasket set matches your specific engine.
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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.