How to Clean Sludge Under Valve Cover

Car engines work best only when they are clean of all impurities. However, if the valves have been blocked with sludge, the consequences might be dire in the grand scale of the vehicle’s performance. So, how do you clean sludge under valve cover?

Well, cleaning the valve of specks of sludge is very easy. You can do so by using an engine degreaser. Alternatively, brake cleaners or carb cleaners can also get the work done. All you need to do is make sure that the liquid reaches every tight corner of the valve.

If you think that this is all you need to follow to get the work done, you are in for a surprise! Scroll down below and keep reading. You will get your areas of interest covered!

What Causes Sludge in Valve Cover?

Sludge Under Valve Cover

Before you can get into the gist of things, you need first to understand the situation that causes this sludgy problem.

Well, several reasons could cause sludge formation in the valve cover. We have compiled and listed some of these reasons below.

Excessive Oiling

One of the most common reasons for sludge formation is excessive oiling. This occurs because drivers might often apply too much oil in their engine than the amount that should be used typically.

Use of Wrong Oil

There is a reason why manufacturers often recommend using a certain type of oil over another that you might think is a good option. When oil with the word carbon density is used, this might cause the oil particles to accumulate in the valve cover and form sludges.

Temperature Changes

When there are sudden fluctuations of temperature to extreme points, this could cause the orientation of the oil to change. As a result, the fluid condenses and can form sludge particles in the valve cover. 

Impurities Mixing In

The automobile will inevitably be exposed to the outside air that carries countless impurities and dirt particles when driving the vehicle. When in contact with the valve, these dirt particles can mix together with the oil and slowly form sludge patches over time.

How to Clean Sludge Under Valve Cover?

clean Sludge Under Valve Cover

Getting rid of the sludge under your valve cover is easy. However, you still need to be well prepared with the right knowledge and tricks and use them to your own advantage depending on the situation you are facing.

Below, we have provided you with three of the most common and easiest techniques that you can opt to follow in order to clean the valve cover. Remember, attempt only one of them depending on which material you have with you!

Engine Flush

The easiest way to clean your engine valve covers is to use an engine flush or sludge remover that is used to remove the patches. It typically takes about 15 to 20 minutes only. All you need to do is apply the chemical to the valve cover and let the engine be in idle mode for 5 to 10 minutes.

Carb Cleaners

While many people often use brake cleaners for removing the grease, we advise you not to do so since brake cleaners may cause unwanted reactions when in contact with the metal parts. Use other cleaners, Castrol degreaser, and gently apply them to the affected area with a bristle brush. If the paint from the metal is affected, you may paint it back.

Dissolve Carbon Deposits

Acetone is a good alcohol source that can dissolve the carbon used to make the sludge. All you need to do is apply small amounts of acetone to the affected area in the vent cover. The reaction will take place, and the sludge will dissolve. 

How Do You Clean Sludge Out of A Cylinder Head?

Clean Sludge Out of A Cylinder Head

If you are looking to clean the cylinder head off sludge, then you need to follow the following step-by-step procedure by letter. Of course, there are alternate techniques in existence. We are only mentioning the one that we think is the best fit.

Step 1: Preparations

First, you need to prepare for the task. Cleaning the cylinder head manually is a dirty chore. Therefore, we advise you to wear goggles and gloves for protection against oiliness.

Step 2: Remove Gasket

If you use a very old car, there are high chances that the gasket will be stuck to the cylinder head. Use plastic scrapers to remove the gasket. However, proceed with caution so as not to scratch the head’s surface.

Step 3: Apply Cleaner

Once separated, apply brake cleaners or carb remover solvents on the head. Only use small amounts since excess fluids can cause the sludge to increase.

Step 4: Soak in Water

After the cleaner has been applied, soak the cylinder head in lukewarm water for a small period. Rinse the head well to remove all excess water droplets after taking it out.

Can You Clean A Valve Cover with Brake Cleaner?

Yes, you can indeed use brake cleaners to clean the valve cover. In fact, brake cleaners are one of the most popular options of cleaning solvents for both the valve and its cover. The following step-by-step procedure follows the processes you need to cover when using brake cleaners to clean the valve.

Step 1: Prepare

Working with the engine and its parts, including the valve, is a dirty task. So prepare yourself beforehand by wearing automobile cleaning gloves or silicone gloves. You can also choose to wear goggles.

Step 2: Remove the Gasket

Remove the gasket manually. If you cannot, simply use a plastic scraper for the procedure.

Step 3: Apply Brake Cleaner

Use a wipe or rug to apply the brake cleaner to the affected area of the cover. Only apply small amounts.

Step 4: Soak and Dry

Soak the cover in lukewarm water for a few minutes and let it dry. Rinse it well to remove excess water molecules before placing it back. 

What Are the Symptoms of a Bad Valve Cover?

There are several signs that can be noticed and identified as symptoms of sludge formation on the valve cover. We have listed some of these points below:

  • Oil is leaking out of the engine valves
  • Burning or leaking oil smell
  • Low energy emission from the vehicle
  • The engine is low on oil
  • The car is not running smoothly


Valve covers might be prone to sludge formation for plenty of reasons. Whether it is due to the weather or simply a mistake with the oil composition, several causes of sludge formation cannot be avoided.

While they might be inevitable, you can learn how to clean sludge under the valve cover conveniently so that they will not implicate the proper running of the vehicle in any situation.

Besides, regularly cleaning valve cover will have significant effects on your vehicle’s engine in the long run!

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