A Guide to Aftermarket Spark Plugs for the 1988-1989 Eagle Medallion
Keep your unique French-American sedan or wagon running right with the correct spark plugs.
- No recalls or major known issues exist for the Medallion's spark plugs.
- Replacement is an easy DIY job that takes less than an hour.
- Choose between affordable standard copper plugs or long-life iridium/platinum plugs from reputable brands like NGK, Denso, or Autolite.
- Always check the spark plug gap before installation.
Signs of Failing Spark Plugs
When spark plugs wear out, they can't create a strong enough spark. This leads to noticeable problems. You might feel the engine shake or vibrate at idle. The car may hesitate or stumble when you accelerate. Other signs include worse gas mileage than usual, a 'check engine' light, or difficulty starting the engine. If you pull a plug out, a black, sooty, or oily tip is a clear sign it's time for a replacement.
Reading the Old Plugs
When you remove the old spark plugs, look at their tips. A light tan or grey color means the engine is running well. If the plugs are black and sooty, the engine may be running too rich. If they are white or blistered, the engine could be running too hot or lean. Oily deposits point to internal engine issues that new plugs won't fix.
Choosing Your Aftermarket Spark Plugs
Since new Original Equipment (OEM) parts for the Medallion are no longer made, you will be using aftermarket plugs. This is not a concern, as many aftermarket brands meet or exceed original quality. The main choice is between different materials, which affects price and lifespan.
Brand & Material Tiers
- Premium Iridium & Platinum (Better): Brands like NGK and Denso offer iridium and platinum plugs. These are top-tier options that provide a long service life and a strong, consistent spark. They are an excellent choice if you want the best performance and durability for your Medallion's French-built engine. Champion also offers iridium options.
- Standard Copper (Good): Brands like Autolite and some NGK or Champion lines use a traditional copper core. Copper plugs offer great performance but have a shorter lifespan than platinum or iridium. They are a reliable and cost-effective choice for a vehicle like the Medallion, but you will need to change them more often.
- Economy Brands (Basic): Brands like Skyward, or other store-brand equivalents, provide a basic, low-cost option to get your car running. While functional, their lifespan and performance may not match that of more established brands.
A Note on ACDelco and Motorcraft
While ACDelco and Motorcraft are OEM suppliers for GM and Ford, their aftermarket plugs are generally considered reliable for other vehicles. They are a solid mid-range choice if available for your Medallion.
Cost of Spark Plug Replacement
| Part Type | Estimated Cost (4 Plugs) |
|---|---|
| New Aftermarket | $13 - $83 |
| Shop Labor | $75 - $150 |
Frequently Asked Questions (FAQ)
Are there any recalls for Eagle Medallion spark plugs?
No. A search of the National Highway Traffic Safety Administration (NHTSA) database shows no recalls or technical service bulletins (TSBs) related to the spark plugs on the 1988-1989 Eagle Medallion.
What is the correct spark plug gap for my Medallion?
The recommended spark plug gap can vary slightly by the plug manufacturer. Some sources suggest a gap around 0.040 inches for Champion plugs, while others list a range up to 0.051 inches for iridium plugs. Always check the specification for the exact plug you buy and use a feeler gauge to verify the gap before installation.
Is it hard to change the spark plugs myself?
No, this is a very beginner-friendly job. The Medallion's 2.2L engine has the spark plugs located right on top and they are easy to access. You will need a basic socket set with a spark plug socket and an extension. The entire job can usually be done in less than an hour.
Should I use copper, platinum, or iridium plugs?
For a classic vehicle like the Medallion, standard copper plugs from a brand like NGK or Autolite are an excellent, affordable choice that matches the original technology. If you prefer a longer service interval and want the latest technology, platinum or iridium plugs from NGK or Denso are a great upgrade.
Do I need to put anything on the new spark plug threads?
Many modern spark plugs, especially those from NGK, have a special trivalent plating that acts as an anti-seize compound and should be installed dry. Applying extra anti-seize can cause you to over-tighten the plug, potentially damaging the engine's cylinder head. Always check the plug manufacturer's recommendation before applying any compound.
Technical Specifications
Thread Size: M14x1.25. Spanner/Hex Size: 16mm (5/8"). Thread Reach: ~17.5mm (0.708"). Gap: Varies by plug, typically 0.040"-0.051".
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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.
- Eagle Medallion: