Exhaust Manifold Turning White: Causes, Prevention & Fixes

By October 15, 2022Common Questions, Exhaust

The exhaust manifold turning white could be caused by several factors, including overheating, engine running lean, exhaust leaks and more. The whitish substances on the exhaust manifold indicate the state of the engine’s underlying problems.  

Personally, I have had my exhaust manifold turn white. When I noticed this, I realized my engine was running too hot. At that time, I did not have a thermostat installed. Once I got the thermostat installed and my manifold cleaned, the problem stopped.  

Why Is Your Exhaust Manifold Turning White?

The primary reasons your exhaust manifold is turning white are heat issues and engine running lean. Other factors could cause your exhaust to turn white. 

Below are factors that make your exhaust manifold turn white. 

1. Overheating 

One of the significant causes of manifold turning white is your engine and exhaust system running at extreme temperatures. When the exhaust system becomes too hot, it will burn up any material from the engine system, making the manifold turn white.

In this case, you need a thermostat for your vehicle. What the thermostat does is that it helps to regulate the running temperature of your engine. The coolant and antifreeze are released when your engine reaches a particular temperature.

Also Read: Car Overheating: Should I Cool Down Car After Driving?

2. Engine Running Lean

When your engine runs lean, it could cause your exhaust manifold to whiten. It means that your engine is burning more air than fuel. When this happens, it could cause your engine to release white fumes. Once the fume reaches the exhaust system, it leaves whitish stains on its parts, including the manifold. 

3. Exhaust Leaking

Your manifold turning white could indicate that you have a leaking exhaust system. When your exhaust leaks, it allows excess air into significant parts of the exhaust system. The air then mixes with the fuel, and the mixture gets burnt once enough heat leaves a white residue.  

Also Read: Exhaust Leak 101: Fixes, Costs & Can You Still Drive It?

4. Leaking coolants 

Coolants are an essential part of the engine system; when it starts to leak, it comes with many signs, including a white manifold. Once the coolants leak, they could get to the exhaust system and get burnt there.  In some cases, the coolants get into the engine system and contaminate the combustion causing white fumes. 

Exhaust Manifold Turning White: Prevention

Your manifold turning white may result from damage to your engine or exhaust system. You can prevent these problems by having a good maintenance culture and regularly checking and replacing the failing engine and exhaust parts.

If you desire to prevent your exhaust manifold from turning white, below is what you could do. 

1. Install a Thermostat 

A thermostat is a device that helps the engine better regulate its temperature. It does this by controlling the release of coolants to the engine. When the engine system reaches a particular temperature, the thermostat will trigger the release of the coolants to reduce the engine’s temperature. Doing this will stop the engine from overheating and burning materials that will make the exhaust manifold white. 

2. Check Exhaust Pipe 

If your exhaust manifold gets white, a most likely cause could be leaking exhaust pipes. You should regularly check the exhaust system for leaks that may allow excess air or other foreign substances into the engine. 

3. Check For Leaking Coolants 

When your coolants start leaking, it could be more severe than you may view it. Try and regularly check your coolant reservoirs and the coolant lines. The leaking coolants could get to the engine and exhaust system and get burnt in the wrong areas. 

4. Make Sure your Engine is Not Running Lean

It is vital to ensure that your engine is not running lean. There are a lot of factors that could cause your engine to run lean. Some of the major causes could be faulty sensors, flawed fuel systems, and exhaust leakage. 

You should ensure that all the factors that could affect the air-fuel mixture are adequately checked. If there is a problem, then you should immediately get it fixed or the damaged parts replaced.

Exhaust Manifold Turning White: The Fixes & Costs

The cost of fixing the exhaust depends on the cause of the manifold turning white. If your exhaust manifold is white, the cost to get the manifold cleaned and other minor repairs will cost around $200 to $500, with an extra cost for labor.

The cost to get your whitened manifold cleaned depends on whether you will be doing it yourself or getting a professional. Cleaning the manifold yourself is easy and will not cost you a dime. 

You must consult your vehicle’s manual to get the manifold cleaned. The tools you will be needing will include steel wool and lacquer thinner. If you are getting the underlying cause of your manifold whitening fixed, it will cost you a lot more. The cost of the fix will vary according to the cause of the problem. 

For instance, if the cause of the problem is a leaking exhaust pipe, it will cost you between $150 to $400. You will also have to clean the exhaust manifold to remove the whitish color and other stains. Do not forget the cost of labor, which will cost above $100.   


Q: What Are the Symptoms of a Clogged Manifold?

A clogged manifold will come with many symptoms, including the following. 

  1. Reduced engine power 
  2. Increased fuel consumption.
  3. Increased noise from the exhaust system 
  4. Burning smell from the engine bay and fuel odor.
  5. Hanging Tailpipe or leaks 


Q: What Are the Symptoms of a Faulty Exhaust Manifold Gasket?

Below are some significant symptoms of a faulty exhaust manifold gasket.

  1. Loud noise from the engine 
  2. Visible exhaust emission 
  3. Increased emission smell
  4. Bad gas mileage
  5. Reduced power generation


Q: Can Exhaust Manifold Cause White Smoke?

White smoke is caused by leaking oil that finds its way into the engine combustion system. The oil is burnt with the air-fuel mixture and contaminates the exhaust fume. It is then passed down to the exhaust system and exits through the manifold. The leaking oil can be caused by a bad valve seal traced to a worn-out piston ring. 

Ifandi L.

Ifandi L.

Passionate about everything mechanical. Ifandi has been involved with motorcycles and cars since the old days - in his family's auto parts shop. Want to keep in touch? Scream "STRAIGHT PIPEEEEE" at the top of your lungs and Ifandi will show up.

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