Honda K20 Engine

The 3 Most Common Honda K20 Engine Problems

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The Honda K20 is a 2.0L inline-4 engine that hit the market in 2001. It’s a part of the popular K-series engines and remains in production today. The success of the engine is no secret as many look to the K20 for engine swaps. Honda’s K20 is a potent engine for its size and offers exceptional reliability. However no engine is perfect and there are no exceptions here. In this article, we will discuss K20 reliability and cover a few of the most common engine problems.

Honda K20 Engine

K20 Engine Variants

Honda’s K20 engine includes the following variants:

  • K20A, K20A1, K20A2, K20A3, K20A4, K20A6, K20A7, K20A9 (2001-2011)
  • K20C1, K20C2, K20C3, K20C4 (2015-present)
  • K20Z1, K20Z2, K20Z3, K20Z4, K20Z5 (2005-2015)

As you may notice – there are quite a few variants of the K20. These engines can be found in cars including the Honda Civic, Civic Si, Civic Type R, and Accord. They’re also in the Acura RSX, RDX, TLX, and CSX. As a vague and general note – some K20’s are higher performance variants that were built to handle the additional power. However, they’re often driven a bit harder and certain maintenance may be more expensive than on lower power models. They also may be more susceptible to problems, especially if pushed hard without proper maintenance.

3 Most Common Honda K20 Problems

  • Front Main Crankshaft Seal Oil Leak
  • Exhaust Cam Lobe Galling
  • Excessive Engine Vibration

We’ll write about these Honda K20 faults below in greater depth. As a note – despite our use of the word common, it’s not always fair to call these common issues. Many K20 owners may not even run into any of the issues we discuss. Additionally, the engine is prone to other faults and failures as with any other engine in the world. The K20 is a great engine, but problems can and do happen from time to time.

Again, it’s a long running engine that is found in many different Honda and Acura models. The engine has also been through its fair share of updates to keep up with modern emissions and power standards. That said, the problems we discuss may affect certain K20’s more than others. Also, as earlier models are 14-20+ years old it’s also fair to assume most problems are fair game due to age and mileage.

Below we will detail the 3 common problems we outlined above. These problems occur on many of the K20 variants, however some engines may be more or less at risk. It’s also fair to assume newer engines like the K20C family will be more reliable in the short-term. Older K20A engines are likely to be a bit less reliable solely due to wear and tear with age. However, if you’re in the market for an older engine, check the maintenance records. It’s possible some or all of these items were already repaired.

1) Front Crankshaft Seal Oil Leaks

A front crankshaft seal is also often referred to as the front main seal. K20 front main seals are responsible for sealing the end of the crankshaft with the timing chain cover. There’s also a rear main seal that seals the crank on the rear side of the motor. Together they are known as main seals. The rear main seal may also develop leaks, however the K20 is mostly prone to front crank seal leaks. The main seals are pretty basic components. They’re literally just seals designed to close off openings at the end of the crankshaft to prevent oil from leaking out.

Over time, K20 front main seals go bad and begin leaking oil from the timing chain cover area. It’s typically not something that instantly turns into a drastic leak. Rather, the rubber seal develops small cracks that allow minor drips of oil to leak. Left alone the leak gradually gets worse. K20 main seal oil leaks typically pop up north of 120,000 miles. Some last the life of the engine while others may be less lucky and experience K20 seal leaks earlier than 100,000 miles. Age and poor oil change history may cause problems to pop up sooner.

Front Main Seal Oil Leak Symptoms

  • Visible oil leak
  • Low engine oil
  • Smoking
  • Burning oil smell

Visible leaks are the most obvious symptom and typically the only noticeable one. Again, the K20 front main seal lies behind the timing cover so look for signs of leaks in that area. If the leak is bad enough you may notice you’re topping off on oil more often than normal. Though, you’ll likely notice drops of oil on the ground before it gets that bad.

Smoking and burning oil smells are very uncommon symptoms of Honda K20 main seal leaks. The oil will likely drip down before it could come into contact with any hot components that would cause smoke or burning oil smells. Nonetheless, it’s possible if the leak is bad enough.

K20 Front Main Seal Replacement Cost

As many likely know, Honda’s are usually pretty inexpensive and simple to repair. This holds true for the K20 front main seal. Labor and seal costs vary depending on your exact year, model, and engine variant. Front main seals should only cost about $10-40. This is great news for the DIY crowd as it’s a very inexpensive repair. Anyone familiar with the basics should be capable of knocking out front main seal replacement on the K20. It may take a few hours for the less experienced, but it’s a straight-forward job.

For the non-DIY crowd, the damage to your wallet still isn’t too bad. Of course, labor costs vary across the world and some of it depends on your year and model Honda or Acura. That said, $200-400 is a reasonable estimate for front main seal replacement at a repair shop.

2) Exhaust Camshaft Lobe Galling

Honda K20 Common Problems - Cam Lobe Galling

Camshafts, also known as cams, sit in the cylinder head and are tasked with opening and closing the K20 intake and exhaust valves. The cam lobes are responsible for controlling intake and exhaust valve lift. It’s hard to depict with words, so we’ve included an image; you can see the physical damage on the K20 cam lobe above. This damage is referred to as cam lobe galling which is fairly common and well documented on the Honda K20. Galling is due to excessive friction on the camshaft lobes. It can cause things like material to weld or connect to the contact point where the friction occurs. It’s also possible that the lobes crack or roughen.

This issue is limited to specific K20 variants, however the problem seems most common on the earlier K20A engines. It’s also important to note – oil that’s too thin or poor oil change history may play a role in K20 cam lobe galling. Most likely won’t run into cam lobe failures. However, it can happen. It’s also worth a mention since it’s one of the more expensive issues that may pop up. Cam lobe galling typically occurs after 100,000 miles.

K20 Exhaust Cam Lobe Galling Symptoms

  • Clicking noise around valve cover
  • Loss of power

This may be a more common issue than we even know about. The symptoms are pretty minor, so it’s possible K20’s are driving around without even knowing they have an issue. Loss of power usually occurs gradually as this isn’t a problem that pops out of nowhere. Rather, power is loss occurs over time as the excess friction continues to wear down the K20’s lobes. The most noticeable symptom is likely a clicking/tapping noise from the valve cover area. You can actually hear the noises from the friction if it’s bad enough.

Exhaust Cam Replacement Cost

Galling normally requires the K20 exhaust camshaft be replaced entirely. The repair is pretty labor intensive so it’s one of the pricier repairs out of the common K20 issues. Honda K20 exhaust cams can typically be had for a couple hundred dollars. Not too bad for the DIY crew. You may even consider using it as an opportunity to upgrade the intake and exhaust camshafts. Upgraded cams offer some performance benefits and hopefully mitigate the chance of running into exhaust cam galling again. Again, it’s a labor intensive job so we recommend only intermediate and/or patient DIY’ers attempt the K20 exhaust cam replacement.

If you end up at a repair shop with these issues expect to pay somewhere around $800-1300. It’s on the pricey side, but fortunately that’s about as bad as it gets for the K20. We come from the BMW world where basically any problem costs that much to fix.

3) Excessive Engine Vibrations

We’ll keep this section a bit shorter. First, there are a few basic maintenance items that can cause K20 engine vibration and rough running. Consider the basics first like spark plugs, ignition coils, dirty throttle body, etc. If none of the basics are responsible for the vibrations then motor mounts should be one of the top items on the check list. This likely isn’t fair to consider as a problem. Engine mounts are responsible for carrying the weight of the engine and partially absorbing bumps, corners, etc.

K20 engine mounts are more of a standard maintenance item. They’re parts that wear down over time. However, engine mounts are common culprits of engine vibrations that may be over-looked. The fact we’re mentioning engine mounts is also a testament to how reliable the K20 is. We’ll skip doing a symptoms section since it’s really just the vibrations.

Engine Mount Replacement Cost

The K20 mounts are pretty inexpensive and can usually be found under $100 for both. You’ll need the right tools for the job, but it’s a pretty basic DIY otherwise. At repair shops expect to pay somewhere in the ballpark of $200-400 for replacement. Not too bad for a maintenance item that shouldn’t need to be tackled until 120,000+ miles.

K20 2.0L Inline-4 Reliability

We’ve mentioned this throughout the post. Nonetheless, we want to reiterate that the K20 is a highly reliable engine. It shouldn’t have any major issues on the road to 200,000+ miles. Some K20 owners won’t experience any of the issues we referenced in this post. At the same time – it’s rare for an engine to eclipse 200,000 miles without at least a few issues along the road. Expect the same concept to apply regarding K20 reliability. Failures can and likely will occur at some point.

Part of K20 reliability boils down to how well it’s maintained. Proper oil weights and timely oil changes are arguably the most important part of basic maintenance. Some reliability simply comes down to the luck of the draw. Regardless, maintain your K20 engine well and chances are it will live a relatively trouble free 200,000+ mile life.

Honda K20 Common Problems & Reliability Summary

The Honda K20 is a long-running engine that’s stuck around for good reason. While it’s been through a fair share of updates the engine remains quality and reliable throughout. Some models and engine variants may be more or less prone to the issues we mention in this post. Long story short: is the Honda K20 reliable? Yes.

However, all engines are prone to occasional faults and this applies to the K20, too. Three of the more common issues include front main seal oil leaks, cam lobe galling, and worn engine mounts. There are a plethora of other one-off issues that may pop up on the K20. This is especially true on early K20 variants as age and mileage takes a toll on any engine. Regardless, expect the K20 to live a long life with above average reliability.

Looking for more Honda K-series engine or Honda Civic articles? Check out our guides including K24 engine problems, K20 vs K24, K20 supercharger kit guide, and common 2010 Civic problems.

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  1. I have thankfully discovered that my K20 in my 2002 RSX base 160hp model is among the most reliable engine of today. In fact I watched a u tube video recently that rates the k eng 2nd best out of 10. I had the oppurtunity to drive a 1975 Honda Civic when it was new. Although the styling wasn’t the best, I could feel this was a “tighter” driving car than my 71 Mustang. The mileage was great also. Now I am proud of my 2002 RSX which has always been adult owned, meaning it’s all origional without all the junk like oversized spoilers or lowered too low. This little 2.0 engine amazes me. No turbo, no supercharging, yet it runs like it does. The car is easy and fun to drive while sipping gas like a hybrid vehicle. I have 110,900 miles on the car and mechanically it is like new. FYI I use 5w30 or 10w 30 full synthetic oil and change my filter at every oil change, (3500 miles). When I get 200,000 miles on the car (if I live that long haha) I’ll post an update and what my plans are for 200,000 to 300,000 miles.

    1. Hi I have the k20a3 motor aswell in a 2005 Honda integra type s 160hp luckily with 5 speed manual I’ve had 2and a half inch exhaust and extractors put on not tuned but yes I’m impressed with how well it goes aswell

  2. I have a K20a3 that just recently ticked over 300,000km. It has started to burn some oil since I’ve owned it, I will be changing the PCV valve and moving permanently to a 5w-30. Thought about using a Lucas additive but changed my mind after reading up on it.

    Mine does have a ticking from the valve cover area, I thought my valve clearances probably need adjusting but maybe the cams have been affected. Closer inspection required.

  3. Hi.I have an Honda Stream 2003 with K20A1 Engine.
    Engine has 339000 km and I noticied a oil leckage that could be front camshaft but I have to verify.
    Engine support passenger side is covered by black oil.
    Do you could confirm that could be from front camshaft?
    Many thanks

    1. Hi Alfredo,

      Sorry to hear that you are dealing with a pesky oil leak. In terms of your problem, it definitely sounds like the leak could be the front main crankshaft seal. That is definitely consistent with the mileage on your engine, especially if the front main has never been replaced before. The other main areas to look would be the valve cover gasket and the VTC solenoid O-ring, which it sounds like you mentioned in another comment.

      It takes a bit of detective work to determine exactly where the leak is coming from, as both the front main crankshaft seal and VTC solenoid are on the passenger side of the engine. If the leak appears to be coming from further forward on the passenger side of the engine, it is likely the front main crankshaft seal which is located behind the front passenger wheel and behind the harmonic balancer. However, if the leak appears to be coming from further back on the passenger side of the engine (closer to the firewall), it could also be the VTC solenoid/O-ring. I’ll include the part number for both of those parts below.

      K20A1 Front Crank Seal Part Number: 91212-PNC-004
      K20A1 VTC Oil Control Solenoid Valve: 15830-RBB-003


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