Honda Oil System Inspection

Almost all engine lubrication systems, including Honda’s, operate the same way in theory. An oil pump generates pressure, oil is sent to the oil galley, and then flows back into the pan. But in practice, it is much more complicated. The oil system practically manages controlled leakage into the oil pan.

The main cause of complaints regarding low oil pressure in Honda vehicles is the oil level. If the oil level is low, the oil intake may open and suck air. The oil level is often associated with the problem of oil consumption. These problems include leaking valve seals and piston ring problems. Another problem is that customers don’t check their oil level regularly.

Oil Pump

The oil pump generates more pressure and volume than needed. Excess volume and pressure is expelled by a relief valve back into the oil pan. Old oil pumps are generally worn out, with sloppy internal clearances and reduced output. Wear between the gears and the housing provides a path for leaks that can hinder the pump’s ability to produce normal volume and pressure. While oil pump failure for Honda inline-four and 3.5L V6 engines is rare, it does occur in some high mileage Honda engines.

The oil pump should be the first check and diagnosis point. Honda usually places the oil pressure sensor between the lower end of the engine and the camshaft.

The pressure output can be checked using the PID data for oil pressure. Information on some machines will not be suppressed in the scan tool; these engines only have a switch that closes when sufficient oil pressure is generated while the engine is started.

Using an external oil pressure gauge is the only way to determine if the oil pump is healthy. At idle, the pressure should be around 10 psi. At 3,000 rpm the pressure should be around 70 psi for a 3.5L V6. For four-cylinder engines, the specified pressure at 3,000 rpm can vary from 35 to 65 psi, depending on displacement and model year.

Oil filter

The oil filter on a Honda engine is known as a full flow filter and is positioned after the oil pump. In most Honda automotive applications this is a spin-on canister filter. Inside the filter is a bypass valve that allows oil to pass through the filter media if it becomes clogged. The filter also has an anti-drainback valve to prevent oil from sucking back into the oil pan when the engine is not running.

If the filter is in bypass mode, the oil will not be filtered. This can damage the engine and cause clogging of the strainer for the variable valve timing system.

If the anti-drainback valve fails, it can delay oil from entering the top end of the engine and camshaft actuators and oil control valve when the engine is started. This can cause noise from lifters and actuators when the engine is first started.

Chain Tensioners

Honda 3.5L V6 uses a chain to rotate the oil pump. It has a tensioner that is powered by oil pressure. The four-cylinder engine uses an oil-powered tensioner for the timing chain. If the tensioner leaks, or if the pressure is too low, the chain can cause noise.

Lower End

Like all engines, oil is used to lubricate bearings and connecting rods. Oil is also used to cool the pistons. The jets are positioned at the bottom of the cylinder. The jets shoot oil at the back of the piston. The oil helps dissipate heat from the pistons and lubricates the cylinder walls. If the oil jet is clogged, it can cause hot spots on the face of the piston. This can cause detonation, pre-ignition and carbon buildup on the pistons.

If the bottom end of the engine isn’t getting enough oil pressure, it’s easily diagnosed by tapping on the connecting rod.

Top End

Oil is pumped to the heads, and supplies oil to the rocker shaft, camshaft and variable valve timing system.

On late-model Honda engines with direct injection engines, oil is pumped into a lobe that drives the high-pressure fuel pump. If oil does not lubricate the lobes and followers, it can damage the camshaft and reduce the amount of pressure the pump can build.

Honda uses an oil pressure powered actuator to drive the camshaft for its variable valve timing system. Oil pressure is supplied to the oil control solenoid which controls the movement of the camshaft.

Because the engine management system is unable to measure the pressure exerted on the oil control solenoid, it looks at the oil control solenoid position and actuator movement to decide if sufficient oil pressure is reaching the variable valve timing system. If movement of the oil control solenoid does not lead to the desired camshaft position, the engine control module will set a code.

The most common code is DTC P1009 for a stuck camshaft in full advance. P1009 is caused if the oil control solenoid is not supplied with sufficient oil pressure. The camshaft advances because there isn’t enough pressure to withstand the force the camshaft lobes exert on the valves.

The oil control valve has a strainer that filters the oil. Mesh filters can catch large particles in the oil before they reach the solenoids or actuators. The filter can be serviced or replaced.

On the side of the oil control solenoid is another screen that catches large debris if the filter fails.

When trying to deal with a possible low oil pressure condition in a Honda engine, stick to the basics first. The first check is with the dipstick. Next, look at the oil. A Honda owner will often use the wrong oil thickness when refueling at gas stations. Once those bases are closed, begin moving up from the pump into the variable valve timing system.