Should You Never Apply Sealant When Replacing the Valve Cover?
2 Answers
Can sealant be applied when replacing the valve cover? Below are the specific details about the valve cover: 1. Aluminum alloy valve cover: Replacing with an aluminum alloy valve cover can provide better sealing, but it's also necessary to check whether the rubber gasket is aged or damaged during installation. If the gasket is aged and not replaced, even switching to an aluminum alloy valve cover won't completely solve the problem. You can use certain engine oils that help soften the gasket, as softening the gasket can enhance the valve cover's sealing. 2. Sealant application: After replacing the gasket, oil leakage issues can be resolved, making sealant application unnecessary. If oil leakage persists after gasket replacement, sealant can be applied to improve the valve cover's sealing, or the valve cover can be replaced altogether. 3. Function of the valve cover: The main function of the valve cover is to protect the engine's camshaft, while also forming a nearly enclosed cavity together with the cylinder head. Inside, there are oil return and supply passages connected to the cavity.
Last time I had my old car repaired, I specifically asked the master mechanic about the valve cover gasket oil leak. He said never to casually apply sealant when replacing it. The original design relies on the metal surface and rubber gasket fitting together for sealing. Applying sealant can actually squeeze into the engine interior. I once saw a young mechanic at a neighboring repair shop haphazardly applying sealant with a glue gun, resulting in sealant particles clogging the oil passages. In the end, the entire engine had to be disassembled for cleaning. Nowadays, reputable repair shops use laser scanning to check the flatness of the cover. If it's deformed, they directly replace it with a new cover and original gasket—applying sealant is purely a lazy shortcut. If sealant must be used, it should only be three tiny rice-grain-sized dots at the corners, and only high-temperature-resistant engine-specific sealant should be used.
