How to Check Engine Timing on a 98 2.5l Subaru: A Step-by-Step Guide

If you own a 98 2.5l Subaru or are simply interested in learning more about car maintenance, one crucial aspect is checking the timing of your engine. Proper timing ensures your car’s engine is running smoothly, efficiently, and maintains optimum performance.

In this article, we’ve put together a step-by-step guide to help you check the timing on your 98 2.5l Subaru. We’ll cover the tools required, what to look for, and any common issues that may arise during the process. So, let’s get started.

Tools Required

Before jumping into the actual process, it’s essential to have the necessary tools to complete the task. For checking the timing on your 98 2.5l Subaru, you’ll need the following:

  • Timing Light,
  • 12mm wrench,
  • A set of jumper wires, and
  • A good quality vacuum gauge.

Steps to Check Engine Timing on a 98 2.5l Subaru

Once you have all the tools at hand let’s proceed to the steps to check the engine timing in your Subaru vehicle:

Step 1: Warm up the engine

The first step in the process is to warm up the engine. Start your car and let it idle for around 10-15 minutes. This will raise the engine’s temperature, giving you a stable reading while checking the timing.

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Step 2: Locate the timing marks

Next, locate the timing marks on your vehicle. You’ll find them at the base of the ignition coil. There might be a rubber cap over them to protect them from dust and moisture.

Step 3: Prepare the engine

Once you’ve located the timing marks, it’s time to prepare the engine. Turn off all accessories such as the radio, fans and ensure the headlight switch is in the off position.

Step 4: Connect the jumper wires

Find the two-pin diagnostic connector under the dashboard on the driver’s side. Connect the jumper wires inside the connector to activate the diagnostic system. The wires are in a small harness and often have a connector over them to protect them from moisture.

Step 5: Attach the timing light

Now, take the timing light and attach it to the battery with the red clip and to the spark plug wire with the black clip. Make sure the cord of the timing light isn’t touching any moving parts such as cooling fans or belts.

Step 6: Adjust vacuum line

Look for the vacuum line that connects to the vacuum advance on the distributor. Unplug it and adjust it so that the timing reaches 10 degrees. Make sure to plug the vacuum advance line back in when you are finished.

Step 7: Check the timing

At this stage, start the engine and point the timing light towards the timing marks you located in step 2. Rev the engine to about 3000 RPM, and the timing mark should appear lit and align to the timing degree you adjusted it to during step 6 on the timing cover. If it’s not aligned, use a 12mm wrench to adjust the distributor to the correct timing.

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Common Issues and Troubleshooting Tips

Although the engine timing check is relatively straightforward, some issues may arise during the process. One common issue is timing advancement. It’s caused when the vacuum advance line doesn’t hold the timing advance properly, and the timing drops, causing reduced performance.

If the timing advancement issue arises in your vehicle, you can try disconnecting it and check that it remains at 10-degree timing. If it does, it means that the vacuum advance is faulty and needs to be replaced.

Another issue is timing belt wear or stretching, causing the timing to be off. In this case, the timing belt would need replacement to ensure proper timing.

Why is Checking Engine Timing Important?

Checking engine timing is essential for maintaining your vehicle’s health and ensuring that it’s running smoothly. Proper timing helps to avoid issues, such as reduced engine performance, increased fuel consumption, and rough engine idling.

If you don’t address these issues, they can cause serious damage to your vehicle’s engine in the long run, leading to costly repairs.


Q. What could cause my engine’s timing to be off?

A. Timing belt wear or stretching, vacuum line issues, or faulty spark plugs or ignition components can cause engine timing to be off.

Q. What is the ideal timing for a 98 2.5l Subaru?

A. The ideal timing for a 98 2.5l Subaru is 10 degrees BTDC (Before Top Dead Center).

Q. Can I check engine timing on my own, or do I need a mechanic?

A. You can check engine timing on your own with the right tools and knowledge, but it’s always recommended to consult a professional mechanic for issues you’re unsure about.

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By following the steps outlined above, you can easily check the engine timing on your 98 2.5l Subaru and identify any issues that need addressing. Regular maintenance and proper timing adjustments ensure your vehicle performs optimally, ultimately, saving you both time and money down the road.

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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.

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