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Frequently Asked Questions
Review Before Installing ■ Are These Genuine, Authentic NGK? Every NGK spark plug sold on OverstockDirect is purchased directly from an authorized NGK dealer in the United States. OverstockDirect has authorization from NGK to sell through Amazon and our online store. Since 1973, OverstockDirect has been a small family-owned and operated business. Never have we sold a counterfeit part. This is an illegal act and one that has no place in our business philosophy. Please email info@NGKsparkplugs.com if you question the authenticity of a product that you have received. When contacting NGK, please provide the country of origin and the lot number on the spark plugs. ■ Are All NGK Spark Plugs Made in Japan? No, NGK has many manufacturing plants based all over the world. While the company’s headquarters are in Nagoya, Japan, NGK has a presence on every continent , with 61 consolidated subsidiaries, 24 manufacturing and sales organizations, and close to 16,000 employees worldwide. Receiving a spark plug from another location is not an indicator that it is counterfeit. NGK’s manufacturing locations are subject to change at any time. If you have unresolved concerns, please contact info@NGKsparkplugs.com for verification. ■ Will These Spark Plugs Fit My Engine? NGK spark plugs are designed to fit specific applications. Please confirm specific fitment data before attempting to install. Please do not use Amazon’s fitment tool as information can be unreliable. Instead, verify official NGK fitment information at the source by clicking HERE. ■ Verify Correct Gap We suggest you consult your vehicle's owners manual to confirm the fitment and gap. This is critical before installing as an improper gap can cause engine damage or worse. Valuable gap and fitment information can be found on both NGK's fitment tool and NGK HERE
■ Check for Damages Upon opening spark plugs, examine product for any damage. Any cracked porcelain, bent terminals or damaged threads can cause poor performance or worse- damage to your engine. ■ Should I Replace One Faulty Spark Plug at a Time or all of Them? We recommended that you replace all spark plugs at the same time. Replacing them one at a time can lead to poor engine performance and damaging your ignition coils. ■ Why is my Engine Running Poorly? Installing spark plugs improperly can cause your engine to perform poorly. If you know you have installed them correctly, we suggest checking your ignition coils to make sure they are compatible. NGK spark plugs have trivalent coated threads negating the need for any anti-seize lubricant. As a reminder, please make sure the gap is correct and the spark plugs are properly torqued to specifications. ■ Should I Apply Anti-seize? No. Anti-seize acts as a lubricant, altering torque values up to 20%, increasing the risk of spark plug thread breakage and/or metal shell stretch. Thread breakage can sometimes involve needing to remove the cylinder head for repair. Metal shell stretch changes the heat rating of the spark plug and can result in serious engine damage caused by pre-ignition. Do not use anti-seize or lubricant on NGK spark plugs; it is completely unnecessary and can be detrimental to your engine. ■ May I Return the Spark Plugs? We are happy to accept returns in the following conditions:
• The spark plugs are still in their original box and unused.
• The spark plugs incurred initial shipping damage.
We will not accept returns on spark plugs that have been modified, installed or used in any way.
■ For additional spark plug installation guides, tips and information, please view below. - What is Spark Plug Indexing? (Video)
- NGK Official Spark Plug Q & A (PDF)
- NGK Spark Plug Replacement Interval (Video)
- NGK Spark Plug Basics (Web page)
- How Do I Install Spark Plugs Correctly?(Video)
- How To Read Spark Plugs; A Complete Guide (Article)
- Iridium Vs. Platinum Spark Plug: What Are The Differences? (Article)
- How To Properly Gap a Spark Plug (Guide)