Subaru XT valve lifter noise issue on Subaru XT

Some Subaru XT owners report experiencing valve lifter noise issues that may require attention. Commonly, noisy valve lifters necessitate replacement, which involves removing the engine to access the cylinder heads. Additionally, hydraulic lifter noise, often exacerbated at idle, can result from aerated oil reaching the lifters due to air drawn past the oil pump seal; replacing these seals is typically recommended. Owners may also notice sudden tappet noise while driving at highway speeds, indicating potential engine problems that warrant further inspection. Cold engine tapping, particularly under power, is frequently attributed to lifter noise, which usually diminishes as the engine warms up. Insufficient oil pressure can lead to valve-related noise, making proper oil pressure crucial for engine function. If the ticking noise is isolated to one hydraulic lifter, it may be a sign of a sticky or collapsed lifter, with the latter often requiring replacement. In some instances, simply replacing the oil pump seals can effectively resolve noise issues, highlighting the importance of prompt attention to these concerns for maintaining engine performance and longevity.