Fixing Oil Pan Leaks In Older Subaru Legacy Models

If you're experiencing an oil leak in your 1999 Subaru Legacy, it's important to identify the source of the leak before attempting any repairs. While the oil pan gasket is a common source of leaks in many vehicles, it's rare for this to be the case in Subaru engines. Other potential sources of oil leaks in Subaru vehicles include the camshaft seals, crankshaft seal, camshaft cap o-rings, valve cover gasket, spark plug tube seals, and the oil separator plate. To accurately pinpoint the source of the leak in your 1999 Subaru Legacy, it's recommended to consult a qualified mechanic or Subaru specialist who can perform a thorough inspection and suggest appropriate repair options.

Confirm the oil pan gasket leak by lifting the vehicle and inspecting the area around the oil pan and engine block

Confirming an oil pan gasket leak on a 1999 Subaru Legacy requires a thorough inspection of the underside of the vehicle. Begin by safely lifting the car and securing it on jack stands. Ensure you have sufficient lighting to inspect the area around the oil pan and engine block.

The oil pan is located underneath the engine and is responsible for collecting and containing the engine oil. Over time, the gasket between the oil pan and the engine block can deteriorate, leading to leaks. When inspecting the oil pan, look for signs of oil residue, dripping, or accumulation on the pan's surface or along the edges where it seals against the engine block. Fresh oil leaks may appear wet and shiny, while older leaks may have a darker, more viscous appearance.

To confirm the source of the leak, clean the suspected area with a degreaser and a rag. Ensure that the engine has been running recently, as this will help identify active leaks. Once the area is clean, carefully observe the oil pan and engine block while the vehicle is running or immediately afterward. If the oil pan gasket is leaking, you may notice fresh oil seeping or dripping from the gasket area.

It is important to note that oil leaks can be challenging to pinpoint, as oil can travel along surfaces and components before dripping or settling in a different location. Therefore, carefully inspect the surrounding areas, including the exhaust, for any signs of oil residue or leaks.

If the oil pan gasket is indeed leaking, it will need to be replaced to resolve the issue. However, before proceeding with any repairs, it is recommended to consult a trusted mechanic or a Subaru specialist to ensure an accurate diagnosis and practical repair solutions.

Place a drain pan under the vehicle and let the old oil drain out

If your 1999 Subaru Legacy is leaking oil, you'll need to identify the source of the leak and fix it. One common source of leaks is the oil pan gasket. If you suspect this might be the issue, you can try to fix it yourself by placing a drain pan under the vehicle and letting the old oil drain out. Here's a step-by-step guide to help you through the process:

Step 1: Prepare the Vehicle

Before you start, make sure you have a drain pan that's large enough to catch all the oil. You'll also need some basic tools like a jack, jack stands, and a new oil pan gasket. Place the drain pan under the vehicle, towards the front. Then, jack up the car and secure it with jack stands. Make sure the car is stable and secure before proceeding.

Step 2: Drain the Oil

Locate the oil plug. It's usually at the back of the oil pan. Place a container under the plug and remove it using a wrench. Allow the oil to drain completely. This may take a few minutes. Once the oil has drained, wipe off any excess with a clean rag.

Step 3: Remove the Old Gasket

The oil pan gasket is located between the oil pan and the engine block. To remove it, first, remove the bolts that secure the oil pan to the engine block. Be careful not to drop them into the oil pan. Then, carefully pry off the old gasket using a flat-head screwdriver or a similar tool. Take your time with this step to avoid damaging the engine block or the oil pan.

Step 4: Clean the Surfaces

Use a clean rag to wipe down the oil pan and the engine block, removing any residue or debris. It's important to ensure these surfaces are clean before installing the new gasket.

Step 5: Install the New Gasket

Place the new gasket onto the oil pan. Make sure it's positioned correctly and lies flat. Reattach the oil pan to the engine block using the bolts you removed earlier. Tighten the bolts securely, but be careful not to over-tighten them.

Step 6: Refill the Oil

Replace the oil plug and lower the vehicle from the jack stands. Open the hood and locate the oil cap. Pour new oil into the engine, following the recommended oil level for your vehicle. Start the engine and check for any leaks. If there are no leaks, your repair is successful!

Remember to dispose of the old oil responsibly. You can take it to a local auto repair shop or recycling center. Do not pour it down the drain or into the environment.

Remove the oil pan bolt, motor mount, oil pan, and old gasket

To fix an oil pan leak on a 1999 Subaru Legacy, you will need to remove the oil pan bolt, motor mount, oil pan, and old gasket. Here is a detailed guide on how to do this:

Remove the Oil Pan Bolt:

• Use a socket or wrench to loosen the oil pan bolt by turning it counterclockwise. This will help you avoid overtightening and stripping the drain plug.
• Once the bolt is removed, check the threads for any stripping or damage. If the threads are stripped, you may need to replace the oil pan bolt.
• Also, inspect the gasket (rubber or metal) for any wear or tearing. If the gasket is damaged, replace the oil pan plug as well.

Remove the Motor Mount:

• To access the oil pan, you will need to raise the engine. This can be done by removing the engine mount bolts and using a jack to lift the engine. Place a piece of wood between the jack and the oil pan to protect it.
• Ensure the engine is raised high enough so that the transmission touches the top of the transmission tunnel.
• Place blocks of wood between the motor mounts and brackets to secure the engine in the raised position.

Remove the Oil Pan:

• With the engine raised, locate and remove all the bolts securing the oil pan. Some bolts may be obscured behind other components, so refer to a service manual for your vehicle to identify all bolt locations.
• Once all the bolts are removed, gently tap the oil pan with a mallet to break the seal, and carefully remove the pan.
• Inspect the oil pan for any metal shavings, clean out any sludge, and check for cracks.

Remove the Old Gasket:

• With the oil pan removed, scrape off any remaining gasket residue from the sealing surfaces.
• Clean all sealing surfaces thoroughly with a solvent to ensure no old gasket material is left behind.

After completing these steps, you can proceed to install a new gasket and reinstall the oil pan. Remember to refer to a service manual or seek guidance from a professional mechanic if you are unsure about any part of the process.

Clean the lower engine block, oil pan, and motor mount

To clean the lower engine block, oil pan, and motor mount, you will need shop rags, a detergent that breaks down oil (such as Simple Green), and plastic or composite scrapers. It is important to avoid using metal tools, as these can damage the soft aluminium engine.

First, use the plastic scrapers to remove large amounts of oil from the flat surfaces of the oil pan. Then, spray some detergent and wipe with a shop cloth or paper towel. For the fins, spray the detergent between the fins and push a shop rag through with one of the plastic scrapers.

Next, use the same procedure to clean the lower crankcase. Remove any partially dried oil from the deep recesses on the outside of the engine, such as the mounts where the engine attaches to the car, with the scraper. Then, spray with detergent and scrub with a shop rag.

Finally, remove the old oil pan gasket. Use a plastic scraper to remove all of it, leaving bare metal, and then use a gasket remover solution to remove any residue.

Apply a thin film of RTV to the mounting surface and install the new gasket

To fix an oil pan leak in a 1999 Subaru Legacy, you may need to apply RTV (Room Temperature Vulcanizing) silicone to the mounting surface and install a new gasket. This process can help seal the joint and prevent further oil leaks. Here is a detailed guide on how to do this:

Before you begin, ensure you have all the necessary materials, including RTV silicone and a new gasket designed for your specific Subaru model. Clean and dry the mounting surface thoroughly, removing any dirt, oil, or debris. It is important to work in a well-ventilated area and wear gloves and eye protection for your safety.

Now, let's get started with the application process:

• Cut the nozzle of the RTV silicone tube at a slight angle to create an opening of about 1/16" to 1/4" (2 to 6mm).
• Apply a thin film of RTV silicone to the mounting surface, ensuring you cover the entire surface evenly. This will act as an adhesive and sealant.
• Surround all bolt holes with the RTV silicone to ensure a comprehensive seal.
• Immediately install the new gasket while the RTV silicone is still wet. This will help create a strong bond.
• Finger-tighten the gasket until you feel the RTV silicone beginning to squeeze out around the edges. This indicates a secure fit.
• Allow the RTV silicone to dry for at least one hour. Then, tighten the gasket to the specified torque settings with a torque wrench.
• Let the RTV silicone cure for a full 24 hours before filling the oil pan with fluid or returning the car to service. This curing time ensures the strongest bond and seal.

Remember, always follow the safety instructions and guidelines provided by the manufacturer of the RTV silicone product you are using. Each product may have specific instructions, so be sure to read the directions carefully. Additionally, it is important to note that RTV silicone is not recommended for use on head gaskets or parts that come into contact with gasoline.

Frequently asked questions