Volvo PCV System Service in Seattle

You might be aware that Volvo’s durable 5-cylinder engines have earned a reputation of racking up impressive mileage. Found across multiple Volvo models including the S60 and XC70, these engines have proven themselves to be the top choice for owners who prioritize reliability and getting decades of use out of their vehicles. 

Part of what keeps these engines reliable over time is maintaining their PCV (Positive Crankcase Ventilation) system. Instead of relying on a single PCV valve, these engines use an oil separator box and a network of hoses and passages to manage pressure inside the engine and return separated oil to circulation. Over time, this system can become clogged, allowing pressure to build and push oil past engine seals and gaskets.

Confusingly, this system might also be called the crankcase ventilation system, flame trap, breather system, or oil separator. While the terminology can get confusing, all of these names refer to components that perform the important job of controlling pressure and oil vapors inside the engine.

At Precision Motorworks, we expertly inspect, service, and replace PCV systems on Volvo engines, especially the 5-cylinder models. Addressing a restricted or failing PCV system before it creates additional problems can help prevent oil leaks from forming and further prolongs the life of your engine. 

What Does the PCV System Do?

During normal engine operation, a small amount of combustion gas makes its way past the piston rings and enters the crankcase. This is known as “blow-by.” Without a way for these gases to escape, pressure would gradually build inside the engine and begin pushing against seals and gaskets.

The PCV system provides a controlled path for these gases to leave the crankcase. Instead of simply venting them into the atmosphere, the system separates much of the suspended oil from the gases and routes the remaining vapors back into the engine’s intake system, where they can be burned during normal combustion.

Why Do Volvo 5-Cylinder PCV Systems Fail?

Volvo’s PCV system is complex and has many possible sources of failure. One common issue is failing diaphragms in the valves themselves. Even more commonly, the system becomes progressively restricted by oil/carbon deposits. Soot and other combustion byproducts continuously travel through the PCV system whenever the engine is running. Over thousands of miles, these materials can create build-up inside the PCV system and, as the system becomes restricted, it becomes increasingly difficult for crankcase gases to escape. Eventually, pressure can build faster than the PCV system can relieve it.

Additionally, since these vehicles (and in turn their engines) are so reliable and used for many years and thousands of miles, age of engine components becomes a notable factor in part failure. Many of the PCV system hoses and fittings are plastic and/or rubber and are exposed to high temperatures over prolonged periods of time. Under such conditions, PCV components can become brittle, cracked, collapse, or otherwise fail. Given the circumstances, a reliable PCV system repair often involves replacement of all relevant components so as to minimize weak points.

Symptoms of a Failing Volvo PCV System

Because PCV problems can cause over-pressurization in the engine, one of the most common signs is increased engine oil loss due to leakage from seals and gaskets. 

When crankcase pressure becomes excessive, it begins pushing outward against the engine’s external components and, in those cases, an engine that previously had only a minor oil seep can suddenly develop a much more substantial leak.

Other symptoms may include excessive oil consumption, high-pitched whistling noises, rough running, or a check engine light. If there is abnormal crankcase pressure, this usually can be detected by removing the oil cap with the engine running to feel how much suction is present. 

Diagnosing the system properly is important because these symptoms can overlap with many other engine problems. The experienced technicians and team at Precision Motorworks, is well equipped to test the crankcase ventilation system and verify the true source(s) of failure, rather than make assumptions.

A restricted or failed PCV system should not be ignored. Excessive crankcase pressure can turn small oil leaks into large ones, making engine repairs expensive. It can also reduce efficiency or cause misfires. 

Volvo PCV System Replacement at Precision Motorworks

PCV systems in Volvos certainly are complicated, but keeping them well maintained and in good working order does not need to be. Regular visits and inspections by the Volvo experts at Precision Motorworks can make it so you never need to worry about the symptoms or consequences of PCV failures, better ensuring your beloved 5-cylinder Volvo can make it to the half-a-million mile mark! Call today to schedule an inspection for your Volvo at Precision Motorworks in Seattle.