Engine Oil Consumption Causes, Symptoms, And Diagnostics!

Engine Oil Consumption Causes, Symptoms, And Diagnostics!

January 11, 2023 0 By CarGuy

Have you started experiencing black smoke coming from the exhaust and the oil level dropped quite significantly? In this case, you probably have increased oil consumption. And if you want to learn the engine oil consumption causes, you are in the right place because, in this article, there will be quite a lot to cover on this topic.

Doing your own research on a certain problem that can happen in a car is always a good idea. The first thing you will do is to inform yourself of about a problem that can occur on your vehicle. Information is the key and really crucial thing in our case because if you are not aware of the problem and you leave your car like that for a long time, you will cause a situation known as oil starvation.

And oil starvation is something that you definitely don’t want. This condition will basically destroy the engine on the inside and your car will eventually stop working or will fail catastrophically from the heat and friction that is created inside the engine block. So, this is why you should follow us closely while we cover the problem.

First, we are going to learn what is oil consumption and whether this problem is a serious issue. Then, we will dive into the engine oil consumption causes and symptoms. Once we clear that out of our way, we will take a look at the next steps that you should take in order to battle this condition. So, if you want to learn more, follow along.

What Is Engine Oil Consumption? Causes?

Now before we delve into more complex topics like the engine oil consumption causes. Let’s first learn more about what is engine oil consumption in general and understand more about it.

As you probably know, the engine is a mechanical device that creates combustion and this combustion simply helps your car move on the road.

And every mechanical device is made out of metal components. And for this purpose, every machine has to be lubricated. If you don’t keep the machine lubricated, the machine will simply wear down prematurely because you will have a lot of metal-to-metal friction.

And metal-to-metal friction is something that you should definitely don’t want. This is why engine oil was invented to help the lubrication of the engine.

Each engine has a dedicated oil type, viscosity, and amount of oil that it should take in order to perform well.

And what is worth noting is that this amount of oil sometimes can be lost between oil changes. So, let’s say that you have an interval of 6,000 miles to flush your oil, and when you reach this mileage, you do the oil change and there is less oil than expected.

So, what does this mean? Well, this means that your car’s engine consumes oil. This is why you have less amount of oil than expected. But what are the engine oil consumption causes, and whether this problem is serious or not? More about that, we are going to elaborate next.

Is Oil Consumption A Serious Problem?

Now let’s take a look at whether this engine oil consumption is a serious problem before we cover the engine oil consumption causes. How serious is this problem?

When it comes to the level of concern that you should implement, we can say that the engine oil consumption really depends on the engine itself.

Some engines, like Toyota engines, for example, can drink a lot more oil than other engines. And as the engine ages and the miles build up on it, this oil consumption will be greater and greater. There really is no fixed number when it comes to oil consumption.

But engines that are less than 50,000 miles, shouldn’t consume more than 1 quart between oil changes. And even 1 quart is a lot of engine oil we must admit.

Engine Oil Consumption Causes

Engines that are higher mileage, can drink more oil. For example, engines above 150,000 miles can consume more oil. So, don’t be surprised that you will have to add even up to 2 quarts of oil between oil changes on a higher mileage engine.

This is why we would definitely not recommend going for a car with more than 150,000 miles. Since many of these cars are heavy oil drinkers.

Sometimes before the engine fails, you can expect to add up to 1 quart per 1,000 miles or less. This is absolutely crazy, and in this situation, you should start looking for a new short block since the pistons of the engine do not seal well and are causing this problem.

But just to make sure, you also have to check the valves. Since the valve stem seals can leak oil and cause excessive oil consumption. But more on the engine oil consumption causes, we are going to elaborate in the following chapters.

Engine Oil Consumption Causes

Now let’s move on and cover the engine oil consumption causes and learn what is causing this problem in the first place.

What is worth noting is that there are a few options on the table when it comes to oil consumption and these are probably the most common ones out there from our mechanic experience. So, let’s cover them in detail.

1. Worn Out Piston Rings

The first in our list of engine oil consumption causes is the situation with the piston rings. These are very thin rings that surround the piston crown or head as some people call it.

There are the compression rings, there are two of these rings, and at the bottom is the oil control ring. When it comes to preventing oil consumption all of these piston rings matter. But the most important one is the oil control ring. As its name implies, this ring does not allow the oil to pass and burn inside the combustion chamber.

And these piston rings over long miles of use and potentially delayed oil changes can seize or break down in pieces.

And once this situation occurs, you have increased wear on the cylinder bore. Once the cylinder bore loses enough material, there will be increased oil consumption.

These situations as we noted, happen both from neglection, as well as from high miles. So, if the engine has high miles in the range of 150,000, you cannot expect it to behave like a brand-new engine.
This is why using high mileage engine oil is recommended, and also doing more frequent oil changes in order to extend the life of the engine as much as you can and hopefully get the most out of it. Now let’s move on to the next engine oil consumption causes.

2. Leaking Valve Stem Seals

The second on our list of engine oil consumption causes is the leaky valve stem seals. So, what are valve stem seals?

As you probably know, engine oil goes on top of the head to lubricate the rocker arms or camshafts, depending on the engine design.

And on each valve, there is a rubber seal that prevents the oil from going down into the combustion chamber.

And these seals are mounted on the valve stems. Thus the name valve stem seals. How they fail is simple to explain, they are made from rubber. And rubber can often become hard and crack over long use.

And when this situation happens, your valves can start to leak oil into the combustion chamber. So, this is why we often recommend inspecting the valve condition before deciding that you need a new engine since sometimes problems lie in the valve stem seals.

You just replace the stem seals and adjust the valves and you no longer have the problem of engine oil consumption. Now let’s move on to the next on our list of engine oil consumption causes.

3. Using The Wrong Engine Oil

Next on our list of engine oil consumption causes is the type of engine oil that you are using. We are listing this reason because people are not using the recommended oil viscosity in some situations.

Remember that viscosity is really crucial in this aspect because your engine was tested with this type of oil and if you put a different viscosity on a good engine, you could damage it and cause issues like in this case with the oil consumption.

For example, if you use very thin engine oil, you could cause engine oil consumption problems. Since your engine was designed to run a thicker oil. This is why before you do any oil change, consult your owner’s manual for the right type of oil that you need to add before you make a mistake. Now let’s continue with the next engine oil consumption causes.

4. Oil Leaks

Next on our list of engine oil consumption causes is not an oil consumption cause technically. But it is a major factor for your engine to waste oil. And this is the situation with the oil leaks.

Oil leaks can be everywhere outside of the engine, the valve cover gasket can leak, and the plastic valve cover can crack and leak. Also, the oil pan gasket can leak.

In addition to these common leaking points, it is worth mentioning the turbo oil feed lines if you have a turbocharged engine, the front and rear main seals, and oil filter housing leaks. Places from where you can lose engine oil are pretty numerous. So, beware of them before you determine that your engine drinks oil.

Engine Oil Consumption Symptoms

Now that we learned more about the engine oil consumption causes, we can move and cover the symptoms of increased oil consumption.

The symptoms associated with this problem will be quite obvious if you have a car that wastes a ton of engine oil. But let’s cover them anyways.

1. Low Oil Level

The first symptom of excessive oil consumption is low oil levels. And this is a tell-tale sign that your engine consumes oil.

So, if you don’t have drops on the ground and the car is constantly having low engine oil levels, then you definitely are having a problem with increased oil consumption. In these cases, your best bet would be to learn the engine oil consumption causes and see what could be causing the problem. Now let’s move on to the next symptom.

2. Poor Engine Work

The next symptom when it comes to excessive oil consumption is poor engine work. This symptom is common on engines that are quite known for these oil-drinking issues.

The engine will perform quite poorly and will not have the energy and acceleration like back in the day when everything was working well.

So, if you notice this loss in performance and the engine seems really slow and poor to respond and lose oil, you know that you have a problem. And more on the problem we will cover next.

3. Low Compression

We listed this symptom separately in order not to confuse people. But when you have poor engine work, this is often due to low compression.

As you probably know, inside the combustion chamber, there should be good compression in order for the engine to work well. And if your compression levels are low and there is an increase in the oil consumption, this means that the engine is pretty worn. And if we look back at the engine oil consumption causes, we can say that this problem is caused by bad piston rings.

4. Blue Smoke

Next on our list of engine oil consumption symptoms is the blue smoke from the exhaust. If your engine drinks a lot of oil, blue smoke is a pretty normal occurrence.

This is also because of the engine oil consumption causes that we listed. Namely, the leaky valve stem seals and the poor piston rings.

So, if you notice something like this, especially when you press your foot on the throttle, it is a good idea to act quickly and tackle the problem. Because if you leave things like this and your car smokes a lot, you can also fail the emissions testing.

5. Carbon Formation On The Piston Top And Valves

Next on our list of symptoms of excessive oil consumption is the carbon formation on the piston top and the valves.

And this is frankly a very common occurrence in cars that waste excessive amounts of engine oil. There will be a lot of carbon gunk on these components that could also prevent them from performing as they should.

So, this carbon buildup can even stop the valves from closing properly and causing a low compression in the process. The most important in our list of engine oil consumption causes that is causing this situation is the situation with the leaky valve stem seals. These seals can make a real mess inside your engine.

6. Clogged Catalytic Converter

The last on our list of symptoms of excessive oil consumption is the clogged catalytic converter. If your engine spends a lot of oil, this is expected.

The honeycomb structure of the catalytic converter has really narrow passageways. And what can happen is that eventually, these tiny holes will end up being clogged up completely.

And when catalytic converters are clogged, exhaust gases does not pass through anymore. So, in this case, the car might seem sluggish until eventually, the honeycomb structure disintegrates into pieces. Which is a sad thing, because these converters are crazy expensive. But how to diagnose high oil consumption based on the engine oil consumption causes? Let’s elaborate more on that next.

How To Diagnose Engine Oil Consumption?

Now let’s take a look at how to diagnose engine oil consumption based on the engine oil consumption causes. What you can do in this case to diagnose this problem on your vehicle?

There are tell-tale signs when it comes to diagnosing this problem. As we noted, the biggest sign is the drop in engine oil levels between oil changes. In this case, your car definitely spends some oil, either from leaks or it is burning this oil in the combustion.

If the loss is because of leaks, you will also have sludge around the place where the leaks come from. If there are no leaks, this means that the engine is burning oil.

And in excessive cases, you will notice blue smoke coming from the exhaust, especially when you thrash the throttle pedal to the floor.

Another way to check is by doing a compression test, or to put a camera through the spark plug hole and see the condition of the bore and see if there is excessive carbon buildup on the piston top. The valves can only be checked if you remove the cylinder head from the engine.

Overall, these are the ways that you can try to diagnose the problem. The engine oil consumption causes will tell everything.

Engine Oil Consumption Repair

So, we learned the engine oil consumption causes and how you can diagnose the problem. Now let’s take a look at the repair options. What you can do in this case?

In this case, you have to open the engine and see what is causing the problem. If the valve stem seals are causing the issue, you have to replace them and resurface the valve seats in order to seal well.

If the problem is caused by bad piston rings, then the only way around will be to either rebuild the engine completely or buy a new short block. A short block is just like a new engine if the cylinder head and the cams are in decent condition. This is why we recommend going for a short block.

Or you can simply purchase a used junkyard engine. But the only downside of this deal is that you never know what you are going to get. When buying a used engine always look for a reputable seller in order not to get scammed by people who look inexperienced people to rip them off. Overall, that’s all you need to know. Now let’s conclude this article on the engine oil consumption causes.

Conclusion To Engine Oil Consumption Causes

In this article, we have covered quite a bit when it comes to engine oil consumption causes. First, we learned what is engine oil consumption and whether or not this is a serious issue on your car.

In the second part, we discussed the engine oil consumption causes, as well as the symptoms that are associated with this condition. Then we learned how you can diagnose the problem and what are the options when it comes to performing a repair on your engine and what are the best options for you on the table if you face a problem with excessive oil consumption.

Overall, we can say that you should opt for a short block if the cylinder head is in good condition. You can purchase an OEM block from the dealership fully assembled, it will be a lot cheaper alternative than going for a full long block.

F.A.Qs To Engine Oil Consumption Causes

Now let’s answer some frequently asked questions.

What Is Oil Consumption

Engine oil consumption is a condition that occurs in an internal combustion engine. This is a situation where you lose a certain amount of engine oil between two oil changes. Certain levels are tolerable according to some engine manufacturers. But if the engine spends too much oil, this means that the engine suffers from excessive oil consumption and has to be repaired if possible, or not, it has to be replaced.

What If Car Loses Oil And Smokes

This means that you have a situation where you have excessive oil consumption. The car simply loses engine oil between two oil changes. And this oil loss is well above the factory-recommended values. And this is why you happen to notice a lot of blue smoke in the rear. This is basically the engine oil that is burning in the combustion process.

What If There Is A Loss Of Oil But No Leak

If there is a loss of oil but no leak, you probably have a problem with excessive oil consumption. The oil has to go somewhere. And in this case, this engine oil probably ends up inside the combustion chamber and is ignited with the gasoline. When a car smokes and loses oil, it is a clear situation that you have an oil-burning issue.