Honda Accord / Acura RDX 2.0T – K20C4 Engine Problems

If you’re a fan of the old school Honda principle of naturally aspirated engines that revved up way past the 7000 RPM mark, then this might not be the car and the engine for you. However, if you’re looking for a reliable turbocharged Honda, this might just be it, and we’ll tell you why that is in just a few moments.

Having proper research done is always a good idea before you decide to purchase a vehicle. This way, you can be sure that you will not end up in a money pit full of problems that will make you regret that you purchased this model. And this is why we are here to help you out with your trouble and help you understand the problems that these engines often carry.

So, what are we going to cover today? Well, first, we are going to learn more about the specs of this engine and see what kind of performance this engine makes. Then, we are going to learn more about the Honda K20C4 engine problems and see what troubles this engine. So, without further ado, let’s dive into the article.

Basic Honda K20C4 Engine Specs

If you don’t know, the K20 engine is probably one of the most popular engines that Honda ever produced.

This engine is a new design that was introduced in 2015 and was conceived to be the engine that will be used in the Honda Civic Type R. So, we can say that the K20 engine is kind of exotic.

But for this article, we are not interested in the most powerful version of this engine that is used in the Type R.

For this article, we are interested in the K20C4 engine that is used in the Honda Accord and the Acura RDX.

Although a non-high-performance engine, in this application the K20 makes serious power after all.

When it comes to the layout of this engine, we can say that this engine is an inline-4 that is very modern and implements the most recent technologies that help it to produce more power and also be efficient.

So, this engine comes with direct injection, variable valve timing, and electronic lift control, as well as a turbocharger.

What is unfortunate is that although called a VTEC engine, this engine does not rev past 6,500 rpm. Which is pretty sad, but that’s the reality nowadays. Naturally, aspirated engines are simply going away and are being replaced with turbocharged engines.

Nevertheless, here are the full specs of this engine that is offered by Honda and Acura.

  • Configuration: inline-4
  • Displacement: 2.0L
  • Cylinder Bore: 86 mm
  • Piston Stroke: 85.9 mm
  • Block & Head Material: Aluminum
  • Head Design: DOHC, 4 valves per cylinder
  • Fuel Injection: Direct Injection
  • Turbocharger: Yes
  • Variable valve timing: VTEC
  • Horsepower: 252 – 272 hp
  • Torque: 273 – 280 lb-ft

Common Honda K20C4 Engine Problems

Common Honda Accord & Acura RDX 2.0T (K20C4) engine problems include:

  • Spark Plug Failure
  • Carbon Buildup
  • Excessive Vibrations
  • Front Crank Seal Leak
  • Cam Lobe Wear

We listed the most common problems, now let’s elaborate on each one of them in detail and see when and how they appear.

1. Spark Plug Failure

The first problem on our list of issues with the K20C4 engine is the situation with the spark plugs. They tend to fail quite often compared to other engines. So, why is this the case?

Well, this is the case because this engine is both turbocharged and also uses direct injection. And these systems tend to be very demanding for the spark plugs.

So, on these engines, you will replace the spark plugs more often compared to the regular Honda engines that are naturally aspirated.

Even though the older Honda engines also go through spark plugs because they rev to almost 9,000 rpm. The good thing is that this engine does not rev that high but still, it has direct injection that somewhat ruins the life of these spark plugs.

Symptoms associated with these spark plug failures include check engine light, rough engine idle, engine misfires, poor fuel economy, and poor engine performance.

Sometimes, the ignition coils can also cause these symptoms. So, if the problem persists after you replace the spark plugs, you can check the coils because they can also fail often on direct injection engines.

2. Carbon Buildup

Carbon buildup is another very common problem with the K20C4 engine. So, what is carbon buildup, and why does it appear in these engines?

Carbon buildup is a situation when there are a lot of carbon deposits that stick to the intake valves. These deposits can become so excessive that they will simply start causing problems with the valves.

The intake valves will not seal well and the engine will lose compression. Resulting in engine misfires and check engine lights.

In these situations, the only way around will be to refurbish the cylinder head. And in order to prevent the problem from reaching this level, you need to do a method known as walnut blasting every 60,000 miles (ca. 96,561 km) or so.

This method can be somewhat expensive but it is the only proven method that will for sure clean off the valves.

You can also try scraping it off, but you will create a bigger mess this way and some of this dirt can end up in the cylinder damaging the engine in the process.

So, be careful and only try the walnut method because it is the only thing that actually works and removes these carbon deposits permanently.

3. Excessive Vibrations

Vibrations are a common thing on these Honda engines. You might be asking yourself, what vibrations, what?

Well, excessive vibrations are reported by owners due to the fact that this is a small displacement engine, the smaller the engine the bigger the vibrations will be.

And what causes these excessive vibrations is the direct injection system. This system injects fuel at a very high PSI and not only that it makes the engine vibrate more but also makes the engine sound like a diesel.

The important thing is that this engine does not have a problem. The normal operation of this engine is like this. So, you shouldn’t be worried much about it. This will not do any harm to your engine.

If you are a Honda guy who has had many Honda engines, you should try to get used to it since the new engines in the future will be all like this.

Now let’s move on to the next Honda K20C4 engine problems.

4. Front Crankshaft Seal Leak

Another very common problem with the K20C4 engine is the leak of the front crankshaft main seal. So, what is this seal and why does it fail?

Well, this is a rubber ring that is installed during the assembly of the engine. It has one purpose and that is to prevent engine oil from leaking outside of the engine.

There are two seals on each of these engines, one for the front end and the rear end. In this case, the one that is leaking is the front main seal.

This is a good thing because you can replace it very easily. An experienced technician can do this job in an hour. The rear seal is much more difficult because the transmission has to be removed.

So, this is a fairly inexpensive replacement. Symptoms associated with this problem are splashes of engine oil on the hood and oil leaks at the bottom of the engine.

These engines are losing a serious amount of engine oil when these seals fail. So, if you are not aware, the problem can even total your engine.

5. Exhaust Camshaft Lobe Galling

And the last problem on our list is the situation when you experience exhaust camshaft lobe galling. So, what are cam lobes and what is this problem all about?

The lobes are the smooth parts of the camshaft, the parts that come in contact with the valve lifters. And these lobes tend to fail on this engine.

Specifically, the exhaust camshaft lobes are the ones that fail the most on the K20C4 engine. Whenever they start the process, there will be increased friction and wear on the camshaft.

This will produce ticking noises, and check engine light as well. There will be codes that indicate problems with the engine timing.

The solution will be to replace this camshaft with a new one. This is the only way to solve the problem. It can be expensive but it is the only way around.

Which Models Have The Honda K20C4 Engine?

  • 2018 – 2022 Honda Accord
  • 2019 – Present Acura RDX


What are the Common Honda K20C4 Engine Problems?

This engine has some issues, but nothing too serious that would stop us from buying it. Namely, there are problems with spark plug failures that can cause misfires and rough engine idle, there is also carbon buildup in the intake ports that requires cleaning (typical for all direct injection engines), galling of the cam lobes can happen on the exhaust camshaft, and there are also leaks from the front main seal.

Is the Honda K20C4 Engine Reliable?

This engine is fairly reliable, it has some issues but nothing too serious. Honda engines usually don’t carry a lot of problems. The most serious problem is the cam lobe galling and the carbon buildup that happens on the intake ports.

About The Author