While not always strictly necessary, applying gasket sealer to valve covers is a common practice among mechanics and DIYers. The primary goal isn't always to create the seal itself, but often to help position and secure the gasket during the installation process.
Is Sealer Required?
According to experienced sources, although valve cover gaskets don't necessarily need sealers or cements, using them is a widespread habit. Modern valve cover gaskets, especially those made of materials like rubber or silicone, are often designed to seal effectively on their own when properly installed and torqued.
However, applying a thin layer of sealer can offer practical benefits during the installation, particularly on valve covers that need to be inverted or maneuvered into place, preventing the gasket from slipping out of its groove.
Why Use Gasket Sealer?
- Gasket Retention: Sealer can hold the gasket firmly in place on the valve cover while you position and bolt it onto the engine head.
- Filling Imperfections: On older valve covers or cylinder heads with minor surface imperfections, a suitable sealer can help fill tiny gaps and enhance the seal.
- Added Assurance: Many choose to use sealer as an extra layer of defense against leaks, though it should not be used as a substitute for a clean surface or proper torque sequence.
Recommended Sealant Choices
When choosing a sealant, it's important to select one compatible with the gasket material and designed for use in the engine environment (withstanding oil and temperature fluctuations).
For this application, several types work well, including:
- Permatex No. 1
- RTV (Room Temperature Vulcanizing) Silicones: Specifically those designed for automotive use, often labeled for oil resistance or high temperature.
- Permatex High Tack gasket sealant
Using the correct type and applying it sparingly (often just a thin bead or smear on one side) is key to preventing issues. Excessive sealer can squeeze out and potentially clog engine oil passages.
In summary, while the gasket itself does most of the sealing work, applying a compatible sealer to the valve cover is a common and often helpful practice to aid in installation and provide an extra layer of leak protection.
