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The K&N Engineering E-3740 replacement air filter is designed to reduce airflow restriction while increasing air flow to the engine. This can help support improved horsepower and acceleration compared with a more restrictive filter. The round filter is designed for installation in the factory air box on specified applications.
Constructed with oiled layers of woven cotton, the E-3740 provides filtration and can be washed and reused repeatedly. K&N states that its replacement air filters can go up to 50,000 miles before cleaning is required, depending on driving conditions. Reusable construction may help reduce the need for repeated replacement of disposable air filters.
The E-3740 is listed to fit 1979 and 1980 Peugeot 604 models. It is also described as fitting certain older Ford Scorpio and Peugeot applications; verify vehicle fitment before purchase. The filter is designed for simple installation and is covered by K&N's Million-Mile Limited Warranty as stated by the manufacturer.
Features:
Order Processing
All orders are processed and shipped within 24 hours of purchase (excluding weekends and holidays).
Orders placed after 3:00 PM EST may ship the following business day.
Shipping Methods
Customers select their preferred shipping method and speed at checkout.
Shipping times are determined by the carrier and cannot be guaranteed by us.
Tracking information will be provided once your order has shipped.
Shipping Coverage
If your package arrives damaged, please notify the delivery driver immediately and contact the shipping carrier to file a claim.
You must report any missing or damaged items within 14 days of delivery.
After this time, we cannot be held responsible for lost or damaged items.
Return Window
You have 30 days from the date of delivery to request a return.
After 30 days, we are unable to accept returns, exchanges, or refund requests.
Eligibility
Items must be returned in their original condition—unused, unwashed, and with all tags and packaging intact.
Certain products may not be eligible for return (e.g., special-order items, customized products, or perishable goods).
Items that have been altered, installed, or modified cannot be returned.
Return Process
Contact our Customer Support team to request a Return Authorization (RMA) before sending items back.
Once your return is approved, you’ll receive instructions on where to send the product.
Customers are responsible for return shipping costs unless the item was defective or incorrect.
Refunds
Refunds are issued to the original payment method once the returned item has been received and inspected.
Please allow 5–10 business days for the refund to appear on your account.
In some cases, a restocking fee may apply (if applicable, this will be disclosed during your return authorization).
