White Sludge On Oil Cap – Should You Be Worried?

White Sludge On Oil Cap – Should You Be Worried?

August 2, 2021 0 By CarGuy

So, you decided to pour some oil into the engine and you have noticed a white sludge on oil cap? What does this mean, a white sludge in my oil? Well, you shouldn’t panic, it’s perfectly normal condensation in most cases, even though sometimes it can be worrying and we are going to explain in this article why.

We all expect oil to be clean but it’s not always the case. The oil inside of the engine is going through many heat cycles and experience a big beating inside the cylinders.

That’s why it is recommended to change every 7,000 miles. This is a good interval if you want to make your engine last forever. The word forever is questionable because everything has a breaking point, but you could manage to do more than 200,000 on most engines.

Regular oil changes and quality oil filter will guarantee the health of your engine and its longevity. But when there is white sludge on oil cap can mean a lot and we have to explain this issue.

In this article, we are going to cover everything you need to know when you are having white sludge on oil cap. We are going to list all of the reasons and the possible outcomes from this issue. So, if you want to learn more you can follow along because there will be plenty to cover.

Why Is There White Sludge On My Oil Cap?

Two possibilities. Blown head gasket or condensation. White sludge may appear from condensation and from a blown head gasket.

What Causes Condensation In Motor Oil?

If you are driving short distances and you notice some white sludge on your oil cap then this sludge is probably caused by condensation. This usually occurs in cold weather when there is a lot of moisture in the air. And this moisture is trapped inside the head of your engine. When the car runs, the oil is mixed with this condensation water and it starts to glue on the oil cap.

Blown Head Gasket

Another reason why there is white sludge on oil cap can be because of a blown head gasket. Head gaskets burn and they cause the coolant to leak inside the oil and make a sludgy mess. This mixture is going to hurt your engine because your oil will start to lose the capability to lube the components like the bearings and the pistons.

This is going to result in premature failure of the engine if not sorted on time. You have to fix this problem on time before you get overheating issues. And they are going to happen sooner or later. The coolant inside of your cooling system will start to vaporize and disappear. The oil will not lube the engine components and will create a lot of friction inside of the engine. Causing the engine to wear off prematurely.

If you have a blown head gasket you will also experience white sludge on the dipstick. So, pull the dipstick and check the oil. If it’s sludgy then you definitely have a blown head gasket. Another symptom of a blown head gasket can be if you are running low on coolant. Check your coolant levels, if they are low then the coolant is probably leaking from somewhere inside of the engine bay or outside under the car. Make a good inspection to see where the leak comes from.

If you are sure that the head gasket is blown, then it’s time to replace it with a new one. We are going to explain how you can do this job in detail from a DIY perspective later in this article. First, let’s see how you can get rid of the condensation.

Solutions For These Problems

As we mentioned, there are two reasons why you have white sludge on oil cap and those were condensation and blown head gasket. In this chapter, we are going to explain to you how you can take care of both of these issues in a DIY fashion.

How To Get Rid Of Condensation In Engine Oil

White sludge on oil can be a big disturbance that can ruin your day, but you shouldn’t worry. If the white sludge is caused by condensation. There are some simple ways that you can fix this issue.

Get a good quality synthetic oil. A good quality synthetic oil will guarantee that there is no white sludge on oil cap. Synthetic oil does not mix with water and can’t create that milky mess. Full synthetic oils can be more expensive but they are worth it in my opinion. This will make you sure that you will not going to experience this issue again.

Another way to solve the white sludge on oil cap problem is by running your car on some long journeys. Let the engine get up to temperature and when the engine reaches operating temperature this condensation will vaporize and you will never going to see it again.

It is a good thing to take your car on the highway and make sure that your run lasts long enough to clean off your oil from all the condensation. This will also clean the carbon deposits that you have collected inside of your catalytic converter so it is a win-win situation for you and your car.

Blown Head Gasket White Sludge On Oil Cap DIY Solution

In this chapter, we are going to cover how you can replace the head gasket on your car. Pay attention that this is not going to work if your head is overheated and is bent. You will need to do machining work on the head before replacing the head gasket in order to level the head.

In order to check if the head is bent, you need to remove the head and place a perfectly straight piece of steel. If there is a gap between the piece of steel and the head. Your engine head will require machining work. We are also going to cover how you can level the head manually but that is going to be after we explain how to replace the gasket. So, let’s begin.

Step 1

Step one requires removing all of the accessories that are above the head. And these include the coils, wires, intake manifold, fuel lines, valve cover. Everything needs to be removed in order for you to reach the head bolts.

Step 2

After you removed everything, now it’s time to remove the head bolts. For this, you are going to need a torque wrench. You need a torque wrench because these bolts are tightened very hard.

Step 3

After removing the bolts now it’s time to remove the head. After you removed the head, place it on a table and clean the head and the cylinders from the carbon buildup and coolant.

Step 4

This is important, you need to make sure that the head is not bent from overheating. You can do this work by placing a perfectly straight metal piece and you will see if there is a gap between the two. If there is then your head will require some machining. If it’s too far gone it may require a completely new head to be installed.

Step 5

After you inspected the head and everything is perfectly straight now it’s time to replace the gasket. Make sure that you hit every hole and the gasket perfectly fits the block. After this, you place the head and torque everything to spec.

Step 6

This step requires installing all the pieces that you removed in the right order and make sure that everything is connected.

Step 7

Drain the oil and the coolant. Make sure that you install new fresh oil and a new filter. Also, add a new coolant that is a 50/50 mixture.

How To Resurface Engine Head DIY?

After the last step, you are good to go. But if your head is bent, you will have to do some machining work. You can take your engine head to a mechanics shop and do the job there or you can do it home on your bench. But in order to do this, you will be required to have a lot of sandpaper and skill. We are going to attach a video of how this work is done DIY. So, if you are considering yourself capable go for it. But I wouldn’t recommend it because you need to be skilled in order to make the head 100% perfect.

Thick Oil On Oil Cap

This is another question that torments owners, what does mean if you have thick oil on oil cap? This means that your oil was not changed for a very long time. Maybe 10,000+ miles.

You should never do this to your car. You will cover the whole engine in sludge that will make your engine run very badly. And possibly ruin the whole engine. When the oil is thick it means that there is no more oiling characteristic left and needs to be replaced.

If you notice this to your engine, change the oil as soon as possible in order to return your engine in perfect condition.


In this article, we have covered a lot when it comes to white sludge on oil cap. We explained why this problem appears and what are the solutions.

It appears because of low-quality oil and condensation from running the car on short distances. Running the car on the highway will probably solve this problem. Also, replace your oil with good synthetic oil that will last for a long time.

And then we have covered the solution if you have a blown head gasket. If you have a blown gasket, it is a good time to replace it before it creates damage to the engine and bent the head. We have written a good DIY tutorial on how you can perform this job at home with a torque wrench and common tools.

We also covered how you can resurface your engine head DIY if you are one of those guys who want to fix their car by themselves. Thanks for the reading and if you liked our article, please follow us on social media to be in touch with the news and our articles that come out daily.