Radium Engineering Universal Air Oil Separator with Return (AOS-R)

A modified, high-horsepower engine tends to generate excess oil and exhaust gases. In these cases, a common oil catch can can quickly fill up and prove insufficient. Like Radium Engineering oil catch cans, the AOS (Air-Oil Separator) kit prevents exhaust oil and other contaminants from entering the air intake system and intercooler (if applicable). The main difference is that an AOS system returns the collected oil to the crankcase, making it maintenance-free.

IMPORTANT INSTALLATION NOTES:

- For the AOS to function correctly, the engine must have a port for oil return.

- The AOS must be mounted high enough in the engine bay so that the bottom port is above the engine's oil return port.

- To prevent condensation, engine coolant must be routed to the AOS-R.

Without a properly designed AOS, water condensation can occur, contaminating the engine oil and reaching the crankcase. Engine coolant lines are routed through the Radium Engineering Air-Oil Separator (AOS) into a specially designed heating chamber (shown above). This keeps the AOS warm and prevents water condensation inside. Because water is denser than oil, a water separator has been incorporated around the lower perimeter, preventing condensation from flowing into the crankcase.

For crankcase to AOS connection, valve cover vents are routed to the upper inlet, where the stainless steel condensing media separates oil from gases. The filtered liquid oil collects at the bottom of the AOS and is routed to the crankcase. Meanwhile, clean crankcase air can vent to atmosphere (VTA) or recirculate to the turbocharger intake pipe. An example of the connection is shown below.

With a properly functioning system, the fluid level inside the AOS will be empty after some downtime. If there is a possible obstruction in the return, simply unscrew the anodized aluminum dipstick to inspect it. Otherwise, the complete unit disassembles into 3 large pieces for servicing.

Benefits

- Effectively increases octane and improves engine performance with cleaner intake air.

- Prevents oil buildup on intake system or intercooler walls, throttle body, intake manifold, etc.

- Reduces hydrocarbon emissions.

Includes

- Radium Engineering machined aluminum Air-Oil Separator (AOS)

- Anodized universal bracket allowing 360° rotation

- Two 5/16" barbed fittings for coolant lines

- Stainless steel hardware

Ports

Top port: 7/8"-14 thread for 10AN ORB fittings

Side port: 7/8"-14 thread for 10AN ORB fittings

Bottom port: 7/8"-14 thread for 10AN ORB fittings

Coolant ports: 7/16"-20 thread, includes two 7mm (or 5/16") barbed fittings

Measurements

AOS Height: 6.3" (without fittings)

AOS Diameter: 3.45" round

AOS Capacity: 20.3 oz (600 ml)

Instruction PDF