JASPER Associate Wayne Hedinger gives this Subaru 2.5L Boxer engine a submersion
pressure test to inspect for leaks.

Oil leaks have been a concern with Subaru’s 2.5L SOHC “Boxer” four cylinder ever since the engine appeared on the market in 1999.

As part of JASPER’s remanufacturing process, every 2.5L Subaru is pressure tested in a tank of water and checked for leaks, before it is live-run tested.

The heads, oil pan and oil pump are installed. All engine ports are sealed off and valve covers are attached. The unit is pressurized with 5 psi and lowered into the tank, where it’s submerged for a minimum of 30 seconds. During that time, Associates check for leaks at the oil pump seal, the cam seals, cam plug, cam cap sealing and the rear seal.

Once the engine passes this inspection, it’s removed from the tank and air dried. All the plugs and fittings are then removed. The water pump and timing components are installed; valves are adjusted and the engine is live-run tested.