DIY Guide: How to Adjust Valves on Your Subaru 2.5 SOHC Engine for Optimal Performance!

If you’re a Subaru owner with a 2.5 SOHC engine, you know that maintaining your engine’s performance is crucial for ensuring your car runs smoothly. One important aspect of engine maintenance is adjusting the valves. Valve adjustment ensures the engine’s valves open and close correctly, allowing the proper amount of air and fuel to enter the cylinders. Adjusting your engine’s valves is an essential part of keeping your Subaru running smoothly, and with the right tools and steps, it’s easy to do at home. In this DIY guide, we’ll take you through everything you need to know about adjusting the valves on your Subaru 2.5 SOHC engine.

Why valve adjustment is important

Valves are critical components in any engine. In Subaru’s 2.5 SOHC engine, there are eight valves that perform a vital role in regulating the flow of air and fuel into the combustion chamber. Inadequate valve adjustment can lead to problems such as poor engine performance, noisy operation, and potential engine damage. Adjusting the valves on your Subaru 2.5 SOHC engine ensures the proper function of the valves, allowing your engine to perform at its best.

Tools required for valve adjustment

Before diving into the step-by-step valve adjustment process, you’ll need to have a few essential tools on hand. These tools include a valve cover gasket, feeler gauges, a 10mm socket, a ratchet, a torque wrench, a 12mm wrench, and a 14mm wrench to adjust the valve clearance.

See also  Unleash Your Subaru's Power: Discover the Subaru Models Compatible with the Dominant VF22 Turbocharger! 🚀

Step-by-step instructions for valve adjustment

  1. Begin by removing the spark plugs from your engine. This will allow you to turn the engine over by hand, making it easier to access the valves.
  2. Next, remove the valve cover by removing the 10mm bolts securing it in place.
  3. Next, locate the first cylinder and adjust the valves for that cylinder. Turn the engine over by hand until the camshaft lobes are pointed away from the valve you are adjusting.
  4. Use a 12mm wrench to turn the adjustment screw until it contacts the valve stem.
  5. Place a feeler gauge between the adjustment screw and the valve stem until you feel a slight drag on the gauge. Make sure the feeler gauge is the correct thickness for the valve clearance specification listed in your owner’s manual.
  6. Use a 14mm wrench to hold the adjustment screw in place and torque the lock nut to the specification in your owner’s manual.
  7. Repeat this process for each cylinder, adjusting the valves in the correct sequence.
  8. Once all valves have been adjusted, re-install the valve cover using a new gasket and torque the 10mm bolts to the specified torque in your owner’s manual.
  9. Finally, install the spark plugs back into place.

Common mistakes to avoid during valve adjustment

While adjusting your engine’s valves can be a straightforward process, there are a few common mistakes to avoid. These mistakes include not following the correct torque specifications when re-installing the valve cover or over-tightening the valve adjustment screws. It’s also essential to adjust the valves in the correct sequence and use the proper size feeler gauge to avoid incorrect valve clearance.

See also  Step-by-Step Guide: Installing Aftermarket Fog Lights on Your 2009 Subaru

Signs that valve adjustment is required

There are a few signs you may notice that indicate it’s time to adjust the valves on your Subaru 2.5 SOHC engine. These signs include noticeable engine noise or a ticking sound, a decrease in engine performance, or trouble starting the engine. If you notice any of these symptoms, it’s important to adjust your engine’s valves as soon as possible to prevent further damage to your engine.

Maintenance schedule for valve adjustment

Subaru recommends valve adjustment at specific intervals. Check your owner’s manual for the specific interval for your vehicle. Typically, Subaru recommends valve adjustment every 105,000 miles for the 2012 and later models.


Adjusting the valves on your Subaru 2.5 SOHC engine is a crucial part of keeping your engine running smoothly. With the right tools and step-by-step process, valve adjustment can easily be done at home. Remember to follow the correct sequence, use the proper valve clearance, and adjust the valves at the recommended maintenance intervals. By keeping up with regular engine maintenance, you can ensure your Subaru performs at its best for years to come.

Avatar photo

Peter Banks

With years of experience as a professional mechanic and Subaru specialist, Peter is one of the most respected members of our team. He's written several articles on Subaru maintenance and repair, and his advice and tips are always practical and helpful. When he's not working on cars, he enjoys cooking and trying out new recipes.

Recommended Articles