This review examines the Denso #5304 Iridium Power spark plugs with clear, practical detail for the interested driver. Key specs: 14 mm thread, 1.25 mm pitch, iridium center electrode, long-life construction, stable gap retention. Performance notes: improved ignition, quick throttle response, typical OEM replacement life. Warranty and returns: 1-year warranty, 30-day return policy. Compatibility, installation torque, and real-world longevity are next—what fits your vehicle?
Key Takeaways
- Denso #5304 Iridium Power plugs deliver consistent ignition and quick throttle response for daily driving.
- Iridium core provides improved longevity and stable gap retention versus standard plugs.
- Thread size 14mm x 1.25mm and 3.62″ length match OEM fitments—confirm vehicle compatibility before buying.
- Sold in sets of four, each plug weighs 5.6 oz; 100% tested at manufacture.
- Backed by a 1-year replacement warranty and 30-day Amazon returns; highly rated (4.5/5 from 980 reviews).
What You Need to Know About Denso #5304 Iridium Power Spark Plugs
Overview: the Denso #5304 Iridium Power spark plugs are a direct-replacement ignition component designed for passenger cars and light trucks.
This paragraph explains core facts: sold as 4 PCS, iridium core, 14mm x 1.25mm thread, weight 5.6 oz, 3.62 x 3.84 x 0.96 in.
How long do they last? Expect improved spark plug longevity versus standard plugs, often reaching recommended intervals when used per OEM schedules.
Expect longer life than standard plugs—often lasting through recommended OEM replacement intervals when properly installed and maintained.
Installation tips: gap specification, torque values, anti-seize use, and sequence adherence.
Q: Warranty? A: 1-year replacement.
Practical note: vehicle-specific fitment must be confirmed before purchase.
Performance, Fitment, and Technical Specifications
Start by examining how the Denso #5304 Iridium Power spark plugs perform across typical driving conditions and how their fitment and specs translate to real-world use. The plugs show consistent ignition, quick throttle response, and measured spark plug longevity from iridium benefits, offering stable gaps and low wear. Fitment: vehicle specific, 14mm x 1.25mm thread, exact OEM replacements. Practical considerations: weight 5.6 ounces, length 3.62 inches, tested 100% at manufacture.
| Feature | Value |
|---|---|
| Thread Size | 14mm x 1.25mm |
| Core Material | Iridium |
| Gap Stability | High |
Q: Ideal for daily driving? A: Yes.
Warranty, Returns, and Customer Ratings
Having covered performance, fitment, and technical specs — including 14mm x 1.25mm threading, iridium core construction, and factory gap stability — attention now shifts to what buyers can expect after purchase: warranty coverage, return options, and how other owners rate these plugs.
Warranty details: Denso backs the product with a 1-year replacement warranty; additional documentation available upon request.
Return process: Amazon.com offers a voluntary 30-day return guarantee, does not affect legal rights.
Customer ratings: 4.5/5 from 980 reviews, best-seller ranks noted.
Q: What to evaluate?
A: Proof of purchase, vehicle fit, and condition when returning.
Frequently Asked Questions
Are These Spark Plugs Compatible With Vehicles Using Coil-On-Plug Systems?
Yes. The responder notes spark plug compatibility with coil on plug systems depends on vehicle-specific fitment; these Denso items are vehicle-specific replacements and are compatible when the OEM thread, heat range and reach match the coil-on-plug application.
Can They Be Used With Ethanol-Blended Fuels or E85?
Yes — like a steadfast companion, they tolerate ethanol blends and E85 while maintaining ethanol performance and preserving fuel efficiency; the iridium construction resists corrosion and wear, ensuring reliable ignition across blended-fuel applications.
Do These Plugs Require a Specific Torque Specification for Installation?
Yes; the installer specifies an installation torque. The technician follows vehicle manufacturer torque values for correct installation torque to prevent damage. Routine spark plug maintenance includes torque checks during replacement and after initial heat cycles.
Are Gap Adjustments Needed Out of the Box?
No — factory settings usually arrive politely pre-set; minimal gap measurement is typically required before spark plug installation. A gentle check reassures fitment, though most users need not perform extensive adjustments out of the box.
Is There a Recommended Replacement Interval in Miles or Years?
Manufacturer recommends replacement frequency around 60,000 to 120,000 miles; longevity expectations vary with driving conditions and maintenance. Owners should inspect periodically and follow vehicle OEM schedules, adapting interval by performance and symptoms.
