If you’re reading this, you’re probably considering purchasing (or currently own) a Honda Motor Company vehicle with the J-series V6 engine equipped with Variable Cylinder Management (VCM). If you want to learn more about the problems with VCM technology causing excessive oil consumption, keep reading.
What is the Honda J-series engine? Honda’s J-series V6 was first introduced in 1996 to replace the C-series V6 and was designed in the United States by Honda Engineers. Displacement for this engine varies from 2.5 liters to 3.7 liters and uses a Single Overhead Cam (SOHC) design utilizing the company’s Variable Valve Timing and Electronic Control (VTEC) to improve performance and fuel economy. Some versions of the J-series include Honda’s Variable Cylinder Management (VCM) technology introduced around 2005 with the Honda Accord Hybrid and Honda Odyssey. With VCM, the engine can automatically switch between running on six or three cylinders depending on load and driving conditions by closing the rear bank cylinder’s valves. In the later 2000s, Honda took the technology a step further by adding the ability for the engine to operate on four-cylinders. What is the issue? Overall, the J-series has proved to be a reliable engine since its introduction nearly 25 years ago. Go on any used car site and you will find several Honda and Acura vehicles for sale with well over 100,000 or 200,000 miles. Since its debut, the J-series’ design hasn’t changed a lot, which has allowed Honda to fine-tune it and work out bugs. VCM variants of this engine, though, are prone to excessive oil consumption. Because the valves on the rear cylinders can close, a vacuum condition develops with the reciprocating effect of the piston still moving up and down. Oil is sucked past the piston rings and enters the combustion chamber to burn once VCM is disengaged. This oil consumption ultimately leads to premature failure of pistons and rings, spark plugs, catalytic converters, and more. Additionally, the electronically controlled engine mounts (designed to reduce vibration when VCM is activated) can prematurely fail, especially if VCM regularly engages and disengages, causing the mounts to wear out faster. When they do wear out, owners will experience significantly more vibration inside the cabin. They are also expensive to replace. What should I do if I own or want to buy a vehicle that has this engine? In dealing with this issue, the solution isn’t as simple as pressing a button to disable VCM, as Honda doesn’t offer that option. It’s possible to override the system with a bypass mechanism, such as a resistor-based temperature override module related to engine temperature. This bypass mechanism basically “tricks” the vehicle’s computer into thinking operating temperature has not been reached, thus not allowing VCM to engage. While this solution isn’t foolproof, it generally will prevent VCM from engaging during normal driving conditions and dramatically extends the life of engine components. If you’re buying a used, high-mileage J-series with VCM, I’d be very cautious, especially about the excessive oil consumption, which will only get worse over time. If your heart is still set on a Honda or Acura vehicle with the J-series, your safest route is to either find one not utilizing VCM or don’t buy one at all. If you currently own a J-series with VCM, check the oil level frequently and change the oil at shorter intervals than what Honda recommends. Should I buy a vehicle with this engine? In the end, I have mixed feelings about this engine and would recommend avoiding it. J-series engines without VCM have been proven very reliable with proper maintenance, easily reaching 200,000 miles. With VCM-equipped versions, it’s still possible to rack up more than 100,000 miles, but the affected cylinders will be in significantly worse condition than the non-VCM cylinders, such as more carbon deposits on the piston head (a result of oil burning), greater piston ring and oil control ring wear (because of the vacuum), and possible piston or cylinder wall scoring, among other problems. Opinion Due to strict emission regulations, automakers have become desperate to find a way to make their engines as fuel-efficient as possible, but this almost always results in lowered reliability due to the effect on the engine itself. I personally have no tolerance for excessive oil consumption with my cars, even slight oil consumption for that matter (and so far none of them exhibit it). Automakers will tell you oil consumption is normal (i.e., one quart every 1,000 miles), but the reality is it is not normal, and that should not be happening if the compression ratios are appropriate according to the durability of the engine’s rings and seals. If one or the other is too great, problems are going to arise eventually. For the sake of achieving maybe a whopping one mile per gallon more in typical driving scenarios, Honda has tarnished the reliability of one of its most acclaimed and renowned engines and angered hundreds of thousands of its owners. Technology such as Variable Cylinder Management may be a good idea on paper, but the keywords here are on paper. In the real world many Honda and Acura owners, who love their Pilots, Odyssey, and Accords, hate this technology and wish Honda would stop using it. If the company would simply put in a button or switch to disable VCM from engaging, many people would be happier because the longevity of their car would be greatly improved. Before buying my current car, I considered a Honda with this engine but decided I didn’t want to deal with oil consumption and premature internal wear. I don’t have regrets. Additional resources More Information About Disabling VCM Now you know the truth behind Honda’s J-series engines equipped with Variable Cylinder Management. I hope you have found this information informative and helpful. Still have questions or comments about this issue? I'd love to help. Feel free to leave them in the comments section below.
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