Description
Product Overview
The Mysttoo Fuel Sealing Washer Kit delivers a reliable, corrosion‑resistant solution for diesel fuel line sealing. Constructed from premium copper, each flat washer offers excellent thermal stability and longevity, ensuring a tight seal under high‑temperature conditions. The kit contains 40 pieces in four diameters—8 mm, 10 mm, 12 mm, 14 mm, and 16 mm—compatible with M8 fasteners, making it ideal for a range of diesel engines and fuel line configurations.
Usage
Designed for Dodge Cummins 5.7 L, 5.9 L, 6.7 L, and 8.3 L diesel fuel systems, these washers also fit any application that utilizes the same 8 mm fuel line dimensions. Whether you are repairing a leaking injector line, replacing worn O‑rings, or performing routine maintenance, the plug‑and‑play design allows quick installation without special tools. Automotive technicians, fleet mechanics, and DIY enthusiasts will appreciate the straightforward fit and immediate leak‑prevention benefits.

Why Choose Us
Mysttoo combines decades of automotive expertise with rigorous quality control. Each washer undergoes precision stamping and dimensional testing to meet OEM specifications. The copper material resists corrosion from fuel additives, while the flat design distributes pressure evenly, reducing the risk of deformation. Backed by a 24‑month quality guarantee, the kit offers peace of mind and long‑term performance.
Key Features
- High‑grade copper construction for superior heat and corrosion resistance
- Flat washer design eliminates gaps, providing a leak‑proof seal
- Includes 40 pieces in five sizes to cover most M8 diesel fuel line applications
- Easy plug‑and‑play installation—no special tools or training required
- 24‑month quality guarantee and responsive customer support
FAQ
What size washers are included in the kit?
The kit contains flat washers with outside diameters of 8 mm, 10 mm, 12 mm, 14 mm, and 16 mm, all designed for M8 fasteners.
Can these washers be used on gasoline engines?
While optimized for diesel fuel lines, the copper material is compatible with gasoline systems that share the same 8 mm line dimensions.
How do I install the washers?
Simply remove the damaged washer or O‑ring, place the appropriate size copper washer onto the M8 bolt, and tighten to the manufacturer’s torque specification. No additional tools are needed.
Are these washers reusable?
Yes, copper washers can be cleaned and reinstalled if they remain undamaged. However, for optimal sealing performance, replacement is recommended when wear is evident.
What warranty does Mysttoo provide?
All Mysttoo fuel sealing washer kits come with a 24‑month limited warranty covering manufacturing defects. Contact our support team for any warranty claims.







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