Honda Civic and Honda CRV Oil Dilution Problem

What causes the Honda Civic Oil and Honda CRV Dilution Problem

Honda Civic oil dilution and Honda CRV oil dilution issues are found on  2016 through 2018 vehicles with the 1.5L Turbo engine.  can experience an oil dilution problem where the oil level in the crankcase rises due to the condensation of fuel and water in the blowby gasses.

The oil dilution is caused by a complicated series of unanticipated events. When Honda switched to direct injection fuel deliver and turbocharging they created the problem themselves. The direct injectors shoot very high pressure gasoline mist direction into the cylinder during the compression stroke. The fuel pressure can reach up to 2,000 psi because the fuel is being injected during the compression stork. The advantage of direction injection is that by injecting during the compression stroke, the fuel can vaporize better and faster because it’s assisted by the heat of compression. (Physics lesson: Any gas heats up as it’s compressed. It’s call the Ideal Gas Law of Physics. Read more here) The higher heat plus the high pressure go a much better job of vaporizing the fuel and that help combustion.

Unfortunately, in the engines affected by the oil dilution issue, Honda engineers, aimed the high pressure injectors directly at the opposite cylinder wall.

When the engine is cold, the fuel tends to stick to the opposite cylinder wall, rather than vaporize. During the power stroke, the extremely high pressure of combustion forces the raw gas past the piston ring gap and into the crankcase. Raw fuel enters the crankcase on many engines and it’s usually vaporized as the engine heats up and the crankcase vapors are circulated by into the intake manifold by the positive crankcase ventilation system (PCV). But during winter, hese Honda engines add more fuel than the engine can burn through the PCV system.

So the raw gas acumulates in the oil pan, raising the oil level.

Does the Honda Civic oil dilution and Honda CRV oil dilution problem cause engine damage?

It can. Overfilling any engine crankcase causes the crankshaft to whip air into the oil causing foam. Foam doesn’t cool well and is easily compressible. So it affects the oil’s ability to remove heat, build pressure and lubricate.

In this case, once the oil level rises to a certain point, owners may notice a whirling noise coming from the engine compartment. That’s the sound of the crankshaft whipping up oil/gas foam.

Worse yet, raw gas not only doesn’t lubricate, but it actually washes lubrication off critical metal parts.

What is Honda doing about the oil dilution problem?

The eventual fix will involve and engine redesign. In the meantime Honda is installing new software that adjusts the pressure and timing of fuel injection on a cold engine. As of August 2019, Honda has tested the software in 190,000 Honda CRVs and 89,000 Honda Civics.

In addition, Honda has issued a warranty extension for those vehicles. The extended warranty adds another year to the powertrain warranty, bringing it to six years. Plus, Honda has eliminated the mileage limits during this warranty period.

Where is the oil dilution problem happening?

Honda has identified 21 states that experience the kind of cold weather that accelerates the oil dilution problem. The Honda Civic oil dilution problem and the Honda CRV oil dilution problem affects as many as 1-million vehicles.

States affected by the Honda Civic oil dilution problem and the Honda CRV oil dilution problem

Maine, Minnesota, North Dakota, South Dakota and Wisconsin Arkansas,
Connecticut, Illinois, Indiana, Iowa, Massachusetts, Missouri, Montana,
Nebraska, New Hampshire, New Jersey, New York, Ohio, Pennsylvania, Rhode Island and Vermont

©, 2019 Rick Muscoplat