TOYOTA 90105-06138 Valve Cover Bolt

The Toyota 90105-06138 is a genuine OEM valve cover bolt with an integrated washer (BOLT, WASHER BASED), ensuring precise and secure fastening of the valve cover to the cylinder head. This premium-quality fastener plays a vital role in maintaining engine sealing, preventing engine oil leaks at the valve cover gasket.

Technical Features and Specifications:

• Type: Hex bolt with integrated washer (Flange / Washer-based bolt)
• Manufacturer: TOYOTA (Genuine OEM part)
• Material: High-tensile, heat-treated steel resistant to engine block operating temperatures and vibrations
• Surface Treatment: Anti-corrosion coating for durability and ease of installation
• Application Area: Securing the valve cover to the cylinder head

Function and Importance:

The purpose of valve cover bolts is to exert uniform clamping force on the valve cover gasket. The integrated washer distributes pressure across the surface of the valve cover, protecting softer materials (such as plastic or aluminum valve covers) from cracking or deformation during tightening. Genuine bolts tightened to the specified torque ensure that the gasket remains leak-free over the long term.

Signs of Wear or Failure:

• Oil Leaks: If a bolt becomes stretched or loosened, the gasket will not seal properly, leading to oil seeping around the edges of the valve cover.
• Thread Damage or Shearing: Overtightening (applying excessive torque) can cause the bolt to stretch or snap, particularly during repeated valve clearance adjustments or gasket replacements.
• Corrosion: Oxidation can weaken the bolt structure, making removal difficult and increasing the risk of breakage.

Note: When replacing the valve cover gasket or removing the valve cover, it is strongly recommended to inspect the condition of the fastening bolts and replace them with new genuine parts if necessary to ensure proper sealing and protect the cylinder head threads.