How to Spot & Fix an Exhaust Manifold Oil Leak

oil leaking from exhaust manifold
Exhaust Manifold

oil leak on exhaust manifold

Car owners often fear the worst when they spot an oil leak under their car’s engine. And if it’s coming from the exhaust manifold, you might wonder what could cause such a mess and how to fix it.

The good news is that diagnosing and addressing an exhaust manifold oil leak is not as complicated as you may think. In this article, we’ll break down exactly what you need to know about these problems, including the common causes and fixes for them so you can get back on the road in no time.

From PCV valves to piston rings and beyond, we’re here to give you a comprehensive understanding of exhaust manifold oil leaks and how to address them to restore your car’s performance. So read on for all the answers!

What are the causes of exhaust manifold oil leaks?

Exhaust manifold oil leaks are one of the most common problems encountered by car owners. They can be caused by a variety of factors, including improper installation, wear and tear, and general corrosion. Here are some potential causes of oil coming out of the exhaust manifold on the tractor:

PCV Valve

One common and easily fixable problem is an exhaust manifold oil leak. To understand why you may have this issue, let’s take a look at the different potential causes and fixes for this engine problem.

First up is the PCV valve. This valve is responsible for ensuring that the pressure inside your engine’s crankcase stays within specified limits. If this valve isn’t working correctly, it can cause oil to leak from the manifold, ruining your engine’s performance. The best way to fix this issue is to replace the valve and make sure it’s functioning correctly before putting your vehicle back on the road.

Valve-Train Seal

The valve-train seal is a part of your vehicle’s exhaust manifold system. It’s what connects the valve train (the valves and other parts associated with your engine) to the exhaust manifold. When this seal wears out, it can cause oil to leak into the exhaust manifold and onto the ground below.

Fortunately, this issue is relatively easy to fix: simply replacing the worn-out seal will usually do the trick! To ensure you’re selecting the correct seal for your vehicle, check with a qualified mechanic or look up your car’s exact make and model.

If you’re up for doing this repair yourself, it’s important to have on hand a few necessary tools: socket set, rubber gloves, oil drain pan, and gasket sealant. Of course, if you’re not comfortable DIYing it or need more guidance, it’s best to leave this repair in the capable hands of a professional mechanic.

Head Gasket

If you’re dealing with an exhaust manifold oil leak, one of the main causes could be your head gasket. If a head gasket has failed, there will be a buildup of pressure in the crankcase, which can cause oil to enter the cooling system and even the exhaust manifold.

Fortunately, the replacement of a head gasket is not overly taxing. The process requires the removal of the cylinder’s head, so you’ll have to mark the orientation of its parts and disassemble any connecting parts. Once that’s done, the new gasket is installed and reassembled—and then checked for proper torque specifications.

Replacing a Head Gasket:

  • Mark the orientation of parts on the cylinder head
  • Disassemble any connecting parts
  • Install new gasket
  • Reassemble and check for proper torque

The Manifold

Exhaust manifold oil leaks are often caused by a cracked or worn-out exhaust manifold. This is especially true if your car is old and has a large number of miles on it. In some cases, the exhaust manifold gaskets can become weak and allow oil to leak out. It’s also possible for the material itself to break down and wear away due to extreme heat or moisture exposure.

You can read: Why car leaking oil after an oil change?

If you think your exhaust manifold is causing an oil leak, here are some of the potential fixes:

  • Replace gaskets

Replacing your exhaust manifold gaskets is often a simple fix that can easily resolve your issue. Make sure you only use the original equipment manufacturer (OEM) parts when replacing these gaskets since generic parts tend to be of lower quality.

  • Tighten bolts

Sometimes all you need to do is make sure that the bolts on your exhaust manifold are properly tightened. This can easily be accomplished with a basic socket wrench set and hand tools.

  • Install a new exhaust manifold

If your exhaust manifold is beyond repair, it may be time to replace it entirely. Again, make sure you’re using OEM parts to ensure maximum performance from your vehicle.

Piston Rings

When it comes to exhaust manifold oil leaks, one of the causes could be an issue with the piston rings. These seals occupy the space between the cylindrical wall and the shaft and prevent oil from entering or exiting your crankcase. When they’re working properly, they keep the oil from leaking into your exhaust manifold.

If your piston rings are faulty, however, you’ll likely end up with an exhaust manifold oil leak. So how can you tell if this is the problem? Unfortunately, you typically need to remove the cylinder head and inspect it yourself. But that doesn’t mean there aren’t other ways to tell—here are a few indications that your piston rings may be worn out:

  • Visible wear on your cylinder walls
  • Increased oil consumption due to poor compression
  • Poor fuel economy due to poor pressure seals
  • Discolored exhaust smoke
  • Excessive amounts of blowy gases

If you catch an issue with your piston rings early enough, you can often fix it by replacing them. Doing so should restore the integrity of your crankcase seal and get rid of any leaks in your engine.

oil leak onto exhaust manifold


One of the biggest causes of exhaust manifold oil leaks is a worn-out piston. The piston changes the pressure of combustion gasses and it fits tightly in its cylinder, so if it begins to wear out, it can start leaking oil.

You can spot a piston problem by looking for oil residue on the outside of the exhaust manifold. It’s also possible that you’ll find oil in the chamber itself, or that you’ll hear an unusual noise coming from your engine, as this is another sign of a possible problem with the piston.

So what can you do if you spot these signs?

  • Replacing the Piston

The easiest fix is to replace your car’s piston. Be careful not to damage any other parts when removing and replacing your car’s pistons—as this could result in even more oil leaks. If necessary, have a professional mechanic come and fix it properly.

  • Cleaning or Replacing Piston Rings

Another option is to clean or replace your car’s piston rings if they are damaged or worn out. Piston rings keep oil from leaking and help to ensure proper compression in the combustion chambers of your engine. Be sure to carefully inspect each ring for signs of wear before replacing them, as they may need replacing regularly depending on how frequently you drive your car.

Valve Guides

When it comes to exhaust manifold oil leaks, one of the main causes is a worn-out valve guide. The valve guide regulates the amount of oil that can enter the combustion chamber and prevents it from leaking out through the exhaust.

When a valve guide is damaged, oil begins to escape through the exhaust, and you’ll notice smoke coming from your engine. If you do have a worn-out or cracked valve guide, then there are a few fixes you can try before replacing it with a new part:

  • Make sure all of your spark plugs are in proper working order and replace any that are broken or corroded;
  • Have your engine serviced regularly to help keep things running smoothly;
  • Adjust your valves as necessary, making sure they’re properly adjusted;
  • Use high-quality motor oil and make sure to check periodically for any leaks;
  • Replace the gasket around the exhaust manifold; and
  • It’s also very important that you get your vehicle serviced by a qualified mechanic to diagnose any problems with your engine.

Fixing an issue with a worn-out or cracked valve guide isn’t always easy, but it can be done. If you take the time to properly maintain your vehicle and ensure everything’s working as it should be, then you should have no problem keeping any leaks at bay.

Head & Block

An exhaust manifold oil leak doesn’t happen out of the blue; there are always causes and solutions. The most possible cause of this type of oil leak is a faulty head & block. So, if you’re experiencing an exhaust manifold oil leak, here are a few things you can do to identify and fix it:

  • Check the Block

The first step should be to check the block itself; a cracked or warped cylinder block could be allowing too much air pressure to escape. If it’s cracked, you may need to have it replaced.

  • Inspect The gasket

Next, inspect the gasket for any warping or damage that could be causing an exhaust manifold oil leak. The gasket should be able to stand up to high temperatures and heat expansion without breaking down. If it’s damaged, you may need to replace it.

  • Examine The Manifold

Finally, examine the manifold itself for any cracks or defects that could be causing an exhaust manifold oil leak. If there’s a crack or defect, you may need to replace the entire manifold.

By routinely checking your vehicle for faults such as these, you can help prevent and repair exhaust manifold oil leaks before they become bigger problems down the road.


Q. How to clear oil leak out of the exhaust manifold?

To clean oil off of an exhaust manifold, start by using a wire brush to remove any loose dirt and debris. Then, use a degreaser to break down the oil. Next, use a cloth or brush to scrub the manifold until all of the oil is gone. Finally, rinse the manifold off with water and dry it with a clean cloth.

Q. How to get oil out of the exhaust system?

Oil takes a long time to burn, especially when mixed with water. Unless you’re burning oil in the exhaust, your best bet is to get it off the highway “hard” and get it hot enough to burn.

Q. What happens if oil leaks on the exhaust manifold?

If oil leaks on the exhaust manifold, it can cause a buildup of oil and carbon deposits in the manifold, which can lead to a decrease in exhaust efficiency and an increase in the risk of engine damage. The oil can also cause the exhaust manifold to overheat, which can lead to cracks and other damage to the manifold.

Q. What causes oil to come out of the exhaust manifold?

A leaking head gasket is the most common cause of oil coming out of the exhaust manifold. Other possible issues include a cracked cylinder head, worn piston rings, or broken piston rings. In some cases, the oil may be leaking from the valve guides or seals.


And there you have it — an overview of the causes and fixes for exhaust manifold oil leaks. It’s easy to overlook these types of problems, but they can have serious repercussions if left unchecked. Pay close attention to the signs of an oil leak, such as noises or smoke, and stay on top of preventative maintenance to ensure that the oil level in your vehicle remains constant. With the right knowledge, you can stay on top of any potential leaks and keep your vehicle running in peak condition.

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I am Engr. Z Eusuf Lubricant Specialist, Mechanical Engineer & has been working with engine lubricants for a long time and knows what makes them work best. I can help you find the right oil for your needs, and I have tips on how to keep your engine running at its best.