Understanding Honda’s 1.5 Turbo Engine: Is Oil Dilution Really a Problem?

by | Mar 10, 2023 | Honda Problems | 2 comments

Do you want to buy a pre-owned Honda but are unsure which engine would be best for you? The 1.5 seems to be the most enticing of the several machines available. You’re likely curious about it. Five turbo engine problems. If that’s the case, we’re here to answer your questions and provide you with all the information you need to purchase confidently.

It would be best to always do your homework before buying a secondhand car. If you don’t do your homework, you may as well purchase a vehicle blindfolded since you have no idea what you’re getting into. There are several options available models-wise. Each of these models has advantages and disadvantages.

Understanding the benefits and drawbacks of a potential purchase is essential for making a wise decision. Acquiring this knowledge can help you save a lot of money over time.

This is why I’m saying it. While you may think the automobile is in good shape at first look, you should know it is not. However, vehicles may still have problems right out of the factory. Furthermore, you can anticipate future repair costs and plan accordingly here.

Any questions you may have about the 1.5-liter engine will be answered here. After getting a foundational understanding, we’ll review the Honda 1.5 turbo issues. Next, we’ll discuss why this motor is worth a look. Well, then, let’s get started.

The Honda 1.5 Turbo Engine

From 2016 onward, Honda has manufactured the 1.5 turbo engine, a compact 4-cylinder engine. This motor is their entry-level offering.

There is a four-cylinder engine in the base model of every Honda vehicle. Although typically in compact or subcompact vehicles that do not need a lot of gas to get around. Let’s talk about the 1.5 specifications first, then dive into some ways it can be used.

The 1.5 has a small turbocharger and four cylinders. Turbocharging helps this 1.5-liter engine generate 174 horsepower. While this engine produces a respectable 158 hp in its base form, the Civic Si’s tuned version with a more significant boost produces 205 hp.

Like most Honda engines, this one has a twin overhead cam. This one has a turbocharger, which makes all the difference. Because of its compact turbocharger and some of Honda’s inventiveness, the 1.5 is the best little and fuel-efficient engine currently available.

In addition to the stated 162–192 lb.-ft. Of torque, the engine’s 174–205 horsepower output is also noteworthy. Those with a higher budget may splurge on the more potent variants, which pack a real punch and are the best option for a high-octane engine.

So what problems are there with the 1.5-turbo Honda engine? Later on in the article, we’ll get our answer. Let’s find out more about turbo engines and how they operate first.

Are Honda turbo engines reliable?

The new Honda turbo engines are generally dependable, although this is not the case everywhere. Like ordinarily aspirated engines, turbo engines function on the same principle but with some modification.

Using the energy from the exhaust gases, the turbocharger spins a turbine to force additional air into the engine. In recent years, turbocharged forced induction technology has become popular because of its efficiency gains.

What this implies is that a reduction in displacement results in an increase in power. Most of these engines use direct injection, so less energy is wasted during combustion.

Unlike multi-point injection, which uses a single fuel pump, direct injection uses two fuel pumps, each powered by a significant amount of boost pressure (2,200 psi in this case). And we’ll talk more about this limitation of direct injection systems when we talk about the issues with the Honda 1.5 turbocharged engine later in this post.

The turbocharger on these 1.5-liter engines is smaller. Thus, there is less visible lag.

And so, what exactly is turbo lag?

The time it takes for the turbo to spool up when you step on the gas pedal is also known as turbo lag. Larger turbos introduce more significant lag and delay in the process.

Because of this, Honda incorporates this ingenious mechanism into their cars to lessen turbo lag and increase driver satisfaction. In turn, this engine is favored by Honda customers. When will Honda fix the issues with the 1.5-liter turbo? Let’s talk about the uses of this engine, and then we’ll go into the problems.


Among several of Honda’s current offerings, you may find the 1.5 turbo engine. As this is not a vast displacement engine, it lacks the muscle to propel some larger vehicles and is thus best suited for smaller applications. But which vehicles do people often utilize the 1.5 in?

To that end, the Honda Civic is a popular option among 1.5-turbo models. Compact and affordable, Honda has been producing the Civic since 1972. The 1.5-liter engine used in the Honda Civic is among the most popular in the company’s lineup.

The Honda CR-V, a compact hybrid among the industry’s top sellers in the United States, is just one more example of a vehicle that benefits from this technology.

The larger Honda Accord car also has this engine. Since it provides the finest performance and fuel efficiency, this engine is standard in all of Honda’s lightweight vehicles.

But what about the troubles with the Honda 1.5 turbocharged engines? Are there significant problems with these engines? In the following chapter, we will find out.


Specifications Values
Compression Ratio 10.6:1 or 10.3:1
Oil Capacity 3.7 quarts (3.5 liters)
Cylinder Count 4
Horsepower Output 174hp to 205hp (peak power at 5,500RPM to 6,000RPM, respectively)
Oil Change Interval Every 9,000 miles (15,000km) or 12 months
Firing Order 1-3-4-2
Cylinder Head Material Aluminum
Valvetrain Type DOHC (Dual Overhead Camshaft)
Bore 2.87 inches (73.00mm)
Torque Output 162lb-ft to 192lb-ft (peak torque at 1,600RPM to 5,000RPM, respectively)
Cylinder Configuration Inline-4
Applications Civic, Civic Si, CR-V, Accord, (Acura) CDX, etc.
Aspiration Turbocharged
Fuel System Direct Injection
Stroke 3.52 inches (89.50mm)
Valves Per Cylinder 4
Displacement 1,498cc or 1.5-liter (91.4 cubic inches)
Cylinder Block Material Aluminum
Fuel Used Gasoline
Technical Designation L15B7


Now we get to the meat of the issue with the Honda 1.5 turbo engines. The 1.5 turbo, like any other engine, is not without its flaws and should be carefully considered before purchase.

There are several issues common to all 1.5-liter turbo engines that you should be aware of before purchasing a secondhand vehicle with one of these engines. Is it impossible to fix these issues? Come on, then, let’s find out.


It’s a well-known quirk of this particular engine. The oil is becoming contaminated by the gasoline, and vice versa. Consequently, the oil will no longer be able to effectively lubricate moving parts like pistons and bearings, leading to poor performance.

Whence comes this unfortunate occurrence? This issue is not due to a manufacturing flaw but rather to the effects of cold weather. Moreover, this Honda oil dilution issue affects the majority of 1.5-liter engines used in colder locations.

This is because this engine takes too long to reach operating temperature. There is petroleum clinging to the inside of the cylinders. The piston rings take the gummy gasoline from the cylinder walls and transport it to the oil. The gas then weakens the oil.

Short-distance drivers in colder areas are the most likely to have this problem. As you make many trips like this, the oil gradually dilutes. There is a significant possibility that the engine parts may wear out quickly due to the conditions in which it operates.

That’s why keeping tabs on your engine’s oil level and condition is essential; otherwise, it’ll wear out fast. In any case, what signs can we look out for if oil diluting?


Experiencing oil dilution may cause various issues, and some telltale signs can help you identify the problem. Some red flags are obvious, while others are more subtle but may point to underlying issues. Which is it, then? Come on, then, let’s find out.

  1. First, there’s a gassy odor when you check the oil. The gas odor may be detected in the oil, which can be confirmed by pulling out the dipstick. There’s a concern if there’s a gas smell (and forcing you to understand how to get gasoline out of clothes). If the oil is old, it will have a burned odor. Yet, there should never be a gas-like odor.
  2. The Oil Level Rises. A rise in oil level is seen if oil is diluted. For this reason, the oil level is raised whenever this occurs. This is due to the oil and gas being combined. If the oil level on the dipstick is above the maximum (and you know where the oil level should be), then you have an engine blending the two fuels.
  3. Overfilling the oil pan might cause the engine to stop, misfire, or lose power, among other problems.


If you reside in a chilly region, you must let the engine warm to the right temperature before driving. In the morning, before heading to work, it’s a good idea to let the car’s engine warm up for a few moments, especially if you have trouble cranking the engine while the vehicle is cold.

Please wait for it to reach operating temperature before putting it to use. If you’re unsure whether to warm up your automobile, a few moments should do the trick. The oil becomes diluted and is no longer usable. Therefore, you should replace it more regularly.

Oil changes every 5,000 miles are recommended. Pay closer attention to the oil’s fragrance and closely monitor the oil level. Indications of gas indicate oil is being diluted.


Carbon accumulation is a common issue with this motor. Is there a particular reason why this engine has been so carbonized? The engine’s direct injection system is to blame for this.

One of the primary problems with these engines is that they are not designed to prevent carbon accumulation. Carbon accumulation is a common problem with direct injection engines. Some are more susceptible than others, while others seem immune to it altogether.

Mostly, carbon deposits form in the head’s intake openings. Extreme carbon accumulation has the potential to block the intake ports, rendering them incapable of forming a tight seal. It may cause the engine to misfire or run at a rough idle.

Carbon accumulation is a common issue with this motor. Is there a particular reason why this engine has been so carbonized? The engine’s direct injection system is to blame for this.

One of the primary problems with these engines is that they are not designed to prevent carbon accumulation. Carbon accumulation is a common problem with direct injection engines. Some are more susceptible than others, while others seem immune to it altogether.

Mostly, carbon deposits form in the head’s intake openings. Extreme carbon accumulation has the potential to block the intake ports, rendering them incapable of forming a tight seal. It may cause the engine to misfire or run at a rough idle.

Problems with Honda’s 1.5-liter Turbo Engine

To what end is this happening? Vehicles using port injection spray gasoline at a greater volume and lower pressure. The effect is similar to that of engine cleaners.

The fuel in direct injection vehicles is blasted at a pressure of 2,000 psi, reducing it to a dusty substance; this is inefficient since oil that bypasses the oil rings isn’t given enough time to be rinsed off the cylinder walls. It leads to a buildup of carbon in the atmosphere.

Over 60,000 miles, carbon accumulation is a common occurrence. For what reason do you need to go beyond 60,000? This occurs when the piston rings have started letting some oil through, signaling the beginning of the issue. What signs might we expect to see as carbon accumulates in the 1.5 turbos? Come on, then, let’s find out.

CO2 Accumulation Signs

These carbon accumulation symptoms in the 1.5 motor are common to all direct-injection engines. All these issues manifest after 100,000 miles when carbon buildup within the engines overwhelms them.

If you own such an engine, it is helpful to be aware of this problem and do some carbon cleaning. After we’ve gone through carbon buildup symptoms, we’ll get to this. Okay, but what exactly are these signs?


Misfiring is a common indication of excessive carbon buildup in an engine. So how can you tell if there’s a malfunction? As they are solely audible, this may not be easy. Little knocks on the cylinder’s top are the typical sound they make.

If you place your palm over the tailpipe while the vehicle runs, you’ll feel little blasts of air. What this signifies is that the motor is significantly misfiring. When there’s a lot of carbon buildup and the engine has never been cleaned, this problem may be frustrating.

The engine is making a rough idle.

There is a correlation between engine misfires and a rough-running engine. This symptom is easy to recognize. The machine is straining to keep up with the constant running.

The tachometer needle swings wildly in both directions. This is because the engine has a rough idle and performs unevenly. This symptom often indicates issues with the ignition.

But, if your vehicle has a direct injection engine, you should also inspect it for carbon accumulation.

Power loss and engine hesitation

A lot of carbon in an engine causes several noticeable issues, including a loss of power and engine slowdown (as when your automobile hesitates while accelerating from a stop). Carbon accumulates on engine valves, preventing a tight seal and disrupting engine operation.

This will lead to signs of low compression and decreased strength. You might lose as much as 50 or 60 hp from the engine. As the issue worsens, it might cause the valve to fail, preventing any compression from happening.

When the engine suddenly stops working, you need to take immediate action. It may also be related to malfunctioning ignition parts. The carbon buildup issue on your list of potential problems is crucial if you own an engine with this design.


Misfires may also cause damage to the spark plugs.


As luck would have it, a technique is developed specifically for removing carbon from direct injection engines. Walnut Blasting is the name given to this process. It’s straightforward: stuff some walnut substance through the valves and blow it with compressed air. Compressed air is used to remove carbon from valves.

Moreover, chemical solutions are put into the valves. After waiting a few minutes, the valves are vacuumed to remove the cleaning solution, leaving them fresh and clean.

Both procedures are expensive; be prepared to spend between $500 and $600.


It’s also important to note the issue with spark plugs on these engines. There are two leading causes for this issue. Increased carbon accumulation within the machine is one culprit; this carbon coats the spark plugs and causes them to wear out. Thus, learning the symptoms of a defective spark plug is essential.

The increased wear on spark plugs in turbocharged engines is another contributing factor. Turbocharged engines are notorious for causing premature spark plug wear. So, you may want to familiarize yourself with spark plug maintenance.

Some poor spark plug symptoms emerge when spark plugs are broken. Sometimes they’re terrible, like when you notice oil inside the spark plug chamber or on the spark plugs individually. So what signs should we look for?


These signs are comparable to those shown by an engine operating with excessive carbon buildup.

Common signs include a sputtering engine, a sluggish response, a jerky idle, and a lack of power.


Changing the spark plugs is the only sure method to fix the issue. A spark plug in one engine should last around 30,000 miles. If you’re curious about the lifespan of spark plugs, there you go.

If you change them now, you won’t have more engine trouble. Each of the four spark plugs costs roughly $10. Hence, the overall cost of replacing spark plugs is reasonable.
This is another task that novice mechanics can do, and I’d suggest it to anybody interested in getting their hands dirty. If you want to understand mechanics, it’s essential to begin with the basics. Nothing beats getting your hands dirty to learn how to solve problems in the real world.

Reliability of the 1.5-liter Honda engine

Despite its reputation for dependability, the 1.5 turbo suffers from several unique issues to Honda vehicles.

If the engine has been properly maintained, these problems are not caused by the alarm. This entails a walnut blasting of the engine and cleaning the intake apertures on the cylinder head.

Problems with Honda’s 1.5-liter Turbo Engine

More regular spark plug replacement is also recommended. These engines’ spark plugs are intended to be replaced more often than in other machines. There are just four of them.

So, many motorists will not have any trouble having them replaced. Even without any special tools beyond a socket torque wrench, this task may be done in the comfort of your own home. If you’re concerned about durability and efficiency, you may compare platinum versus iridium spark plugs. Instead, you may compare and contrast spark plug manufacturers like NGK and Denso.


This engine has a decent lifespan, lasting over 150,000 miles before experiencing any problems. Following the tips outlined above should help this engine last even longer.

The best course of action when considering the purchase of a car equipped with this engine is to have the automobile inspected to determine the engine’s condition. Check the engine’s power and the transmission’s shift points. As a result, you can be confident that the motor is in excellent working order and that the drivetrain will not let you down.

Nonetheless, automobile mishaps are always a possibility. Let’s aim for the best, however, which is worry-free property ownership. The fundamental engine is, after all, quite dependable and sturdy. Since then, Honda has made several advancements as well.


Much ground about the Honda 1.5-liter engine has been covered here. The engine’s specifications and displacement were revealed to us. In the second part, we spoke about turbo engines and their advantages.

We then focused on the article’s primary topic—issues with Honda 1.5 turbo engines. There are several known problems with this engine. In colder climes, oil dilution was a common problem for engines. The direct injection technology and the spark plug failure problem contributed to the accumulation of carbon.

All of these issues are minor and simple to fix. Oil contamination may be avoided by increasing the frequency with which carbon deposits are removed and waiting for the engine to reach operating temperature before setting off first thing in the morning. Ignition problems may also be avoided by increasing the frequency of replacing the spark plugs.

Questions and Answers About Honda 1.5 Turbo Engine Problems

Check out our frequently asked questions to see if we can help clear up any remaining confusion about the Honda 1.5 turbocharged engine issues.

Problems with the 1.5-liter turbocharged engines in Honda Accords

One of the issues with the Honda 1.5 turbocharged engine is that it cannot heat up properly when idling. As a result, drivers in colder regions may have longer wait times until the engine is sufficiently warmed up. It may take a while to become hot enough before you can drive. Condensation occurs on cold machines, and the engines release more gasoline vapors. All of that extra gas might water out the engine oil. Carbon accumulation on the intake valves is another drawback of its direct-injection layout. When coupled with that chilly engine, the situation becomes much direr.

Difficulties with the 1.5-liter turbocharged engines of Honda Civics

The Civic shares the same problems as the bigger Accord, although to a lesser extent since it has a lower-tuned version of the 1.5-liter turbo. The engine suffers from fuel-oil dilution, which is more common in colder locations. The 1.5-liter turbocharged engine is quite productive, but its slow warm-up time is a significant drawback. Unburned fuel vapors now cling to the insides of the cylinders. When this happens, the oil absorbs it and waters it down. As a result, the oil diluting problem now combines with two other significant issues. For starters, there is a substantial amount of carbon buildup on the intake ports. The spark plugs were also susceptible to fouling.


Fortunately, by 2021 and 2022, Honda had resolved most issues with their 1.5-liter turbo engine. Oil dilution was the main problem with the 1.5 turbo engines, which led to further problems. Since the 1.5-liter turbocharged engine takes so long to heat up, particularly in low temperatures, this is a common complaint. Honda’s solution was a minor adjustment to the electronic control unit. As a result, the 1.5-liter turbo engine might be a little richer. Honda also sent part of the interior heat to the machine to speed up the process.


Hondas are among the most dependable automobiles available. Count on them to last you a reliable two hundred thousand to three hundred thousand miles. With regular upkeep and care, the lifespan of this device might be increased much further. Their owners have trusted Hondas for as long as twenty years in certain situations where they’ve had very few problems compared to the average automobile.

In 2021, did Honda resolve the oil diluting issue?

Honda’s engines still have this problem in 2021, despite a software update that helps them heat up more (the primary source of oil dilution). In particular, oil dilution remains a problem in 2021 and 2022 for the 1.5 turbocharged Earth Dreams engines. Only regular oil changes can prevent engine oil from diluting to dangerous levels. Therefore drivers should schedule their oil changes accordingly. Sure, vehicle owners recommend oil changes at least every three thousand miles.


In most cases, turbocharged engines may be expected to serve their owners well, provided that they are not too tuned and modified. Many turbo-diesel vehicles, for instance, may go up to 250,000 miles before needing an engine repair. There may be some who can go even more than half a million miles. The same ideas also apply to everyday passenger vehicles; turbocharged engines are just as durable as ordinarily aspirated ones. Good maintenance is required to keep it going for a very long period. This involves getting the oil changed regularly, using high-quality motor oil, and observing a cool-down period before turning off the engine after use.

Can You Trust A 1.5 L Engine?

The 1.5-liter engines Honda produces are among the best in the industry. Many advantages may be realized from a 1.5-liter displacement, particularly when combined with one or more turbochargers. Honda was able to get respectable performance out of a relatively compact engine. Nonetheless, it still has the advantage of reducing the displacement to a smaller size. The benefits extend to decreased emissions and enhanced fuel economy. On top of that, Honda’s 1.5-liter engines are among the most dependable in the industry, with very few significant problems. Hence, it is the master of all crafts, admirably combining potency, efficiency, and dependability.


  1. So what do I do if this has already happened and all the negative reactions that could possibly occur, did occur. My 2019 Honda Civic EX Hatchback has 68,000 miles on it and my mechanic said to get rid of the car. I had regular oil changes performed on the car since the day I purchased it brand new. Honda was aware of the problem. They should have fixed it or at least warned their buyers that regular oil changes are not enough to keep the engine running for more than a few years (or even enough years to pay the car off). In my opinion, this is very irresponsible of Honda. I have always known Honda to be the best and most reliable. Obviously, I was majorly mistaken. (A very costly error). Thank you for posting this article. After hours of searching the web, I came across this. This is exactly what happened to my car. It explains everything my mechanic told me was going wrong. He has to keep replacing the same things over and over again (spark plugs). The car is burning over 7 quarts of oil every few weeks. The car drives horribly and cannot even pick up enough speed to merge onto the beltway. Some days the car will only go a maximum of 8 miles per hour. Your article helped me to understand why all of these things are going wrong. It helped me to see what crooks Honda really is, and I think it covered that I need to find a way to purchase another vehicle. If the Hinda dealership would have told me about the problems with the engine, even 6 months ago when I took it there bc the issues were beginning, maybe I could have followed some of your suggestions and kept it from getting so bad.

  2. Has anyone looked at carbon buildup on the intake valves after say 100K miles? Any idea of the expense to clean the intake valves, if carbon buildup should become a problem?


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Drawing from extensive expertise in the used car parts industry, Craig Sandeman has established himself as a trusted authority in automotive repair. He possesses a deep knowledge of the challenges encountered by individuals seeking reliable car parts, making him a highly sought-after expert in this field.


Potential issues, causes, and solutions have been identified in the above article based on the experiences of car owners and repairers, as well as web materials such as forum blogs and technical support bulletins. This data is supplied exclusively for the purpose of reference. Only appropriately qualified persons should perform repairs and/or changes on your vehicles.

While it’s important to keep in mind, it’s also important to note that the amount of times anything is mentioned here should not be seen as a sign of its reliability or frequency. Various owners, driving in different ways, and caring for their vehicles in distinct ways will cause two identical vehicles to perform differently.

As previously said, this material is supplied primarily for reference reasons; nonetheless, we hope that by doing so, we will be able to supply you with essential knowledge that will allow you to make informed decisions whenever you encounter any of the aforementioned setbacks.


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