VAG/PORSCHE 059103495G OIL SEPARATOR
Product Specifications
| VAG/PORSCHE | 059103495G |
The OIL SEPARATOR is the crankcase ventilation oil separator — also called the catch can, PCV oil trap, or breather separator — that removes oil mist and oil droplets from the blowby gases vented from the crankcase before those gases are recirculated into the intake manifold by the positive crankcase ventilation (PCV) system. During normal engine operation, a small quantity of combustion gases passes the piston rings into the crankcase on each compression stroke — this blowby gas contains fuel vapour, water vapour, and combustion soot that would contaminate and dilute the engine oil if allowed to accumulate; the PCV system continuously evacuates this gas from the crankcase using intake manifold vacuum, returning it to the combustion chamber for burning. However, the crankcase gas also carries a significant quantity of oil mist — fine oil droplets and vapour generated by the rotating crankshaft and piston assemblies splashing in the oil sump — that must be removed before the gas reaches the intake manifold to prevent oil from depositing on the intake valves, intercooler, throttle body, and MAF sensor. The oil separator achieves this separation through a combination of impingement — directing the gas stream against baffles or cyclone chambers where oil droplets collide and coalesce — and gravitational settling — collected oil drains back to the sump through a drain tube while the de-oiled gas continues to the intake system.
This unit — VAG/PORSCHE 059103495G — is manufactured to OEM-equivalent specifications: separator housing dimensions and internal baffle geometry for the correct separation efficiency at the engine's blowby flow rate, inlet and outlet port sizes and positions, drain tube connection geometry, pressure relief valve or PCV valve integration where applicable, mounting bracket positions, and material compatibility with the engine's oil specification are matched to the original part. Supplied as a direct replacement for standard fitment. Available wholesale from 8.67 USD, MOQ 50 pcs, production lead time 23 days.
Oil separators fail through internal sludge accumulation that progressively blocks the baffle passages, reducing separation efficiency and eventually blocking the crankcase ventilation path entirely — a blocked separator forces crankcase pressure to build and push oil past the rear main seal, valve cover gasket, and front crankshaft seal; through cracking of the plastic housing from thermal cycling and age embrittlement; and through the integrated PCV valve sticking open or closed. Oil separator blockage is almost always caused by extended oil change intervals that allow the oil's detergent package to deplete and sludge to form — maintaining OEM oil change intervals is the primary preventive measure for separator longevity.
- Clean all connected hoses and the intake manifold connection port before fitting the new separator — sludge and oil deposits that have accumulated in the ventilation hoses will be dislodged by the fresh gas flow through the new separator and redeposit inside the new unit within a short period, rapidly re-blocking it; flush the hoses with brake cleaner or compressed air and wipe the intake manifold port clean before any connection is made to the new separator.
- Inspect the oil drain tube from the separator back to the crankcase or sump for blockage and correct routing — the drain tube must slope continuously downward from the separator body to the crankcase return point without any upward loops that would trap collected oil; a kinked or incorrectly routed drain tube prevents separated oil from returning to the sump and causes the separator to flood internally, reducing its separation efficiency to near zero and forcing oil-laden gas to bypass the baffles.
- Replace the integrated PCV valve simultaneously with the separator on designs where the PCV valve is part of the separator body — a PCV valve that is stuck open allows excessive blowby gas flow that carries more oil mist than the new separator can handle; a PCV valve stuck closed blocks all crankcase ventilation and rebuilds crankcase pressure immediately after the new separator is installed; on designs where the PCV valve is separately accessible, test it by shaking — a functional PCV valve rattles freely; a stuck valve is silent.
- Verify all hose connection clips and clamps are correctly seated and locked after connecting the new separator — the crankcase ventilation circuit operates at negative pressure (intake vacuum) on the outlet side; a loose hose connection allows unmetered air into the intake downstream of the MAF sensor, producing lean fuel trim codes that are identical in presentation to a MAF sensor fault and will persist until the air leak is sealed.
- Perform an engine oil and filter change immediately after fitting the new separator — the oil that has been circulating in an engine with a blocked separator contains accumulated sludge and combustion products that will rapidly contaminate the new separator's internal baffles if not removed; fresh oil of the correct specification is essential to maximise the new separator's service life from the first operating hour.
- Install the new OIL SEPARATOR (VAG/PORSCHE 059103495G), reconnect all ventilation hoses, start the engine and run to operating temperature, then remove the oil filler cap momentarily — there should be no strong suction or pressure felt at the filler neck with the engine idling; strong suction indicates the separator drain is blocked; strong blowout pressure indicates the separator outlet is blocked; confirm normal crankcase pressure and check for oil leaks at all disturbed connections before returning the vehicle to service.
| Part | Reason for Combined Replacement |
|---|---|
| PCV Valve OEM ref. varies — may be integral or separate | The PCV valve controls the flow rate of crankcase gas through the separator and is subject to the same sludge contamination as the separator body. A stuck or partially seized PCV valve produces either excessive crankcase pressure (stuck closed) or excessive oil mist flow that overloads the new separator (stuck open). Always replace the PCV valve simultaneously with the separator — on designs where the valve is integral to the separator housing, both are renewed together automatically. |
| Crankcase Ventilation Hose Set Application-specific rubber or plastic hoses | The ventilation hoses connecting the crankcase outlet, separator, and intake manifold accumulate internal oil sludge deposits over the same period as the separator. Installing a new separator on old sludge-contaminated hoses deposits sludge into the new unit's internal passages from the first minute of operation, dramatically shortening the new separator's service life. Replace all ventilation hoses simultaneously with the separator to provide the new unit with clean inlet and outlet paths. |
| Engine Oil and Oil Filter Grade and specification per OEM requirement | An oil separator that has blocked is invariably surrounded by oil that has degraded beyond its detergent capacity and is generating the sludge that caused the blockage. Fitting a new separator without changing the oil reintroduces the same sludge-generating environment from the first start. Always perform a complete oil and filter change immediately after separator replacement and consider a repeat oil change after the first 1,000 km to flush residual sludge from the circuit before it reaches the new separator. |