Abstract: An acid neutralizing filter construction is provided that may be used as a bypass type filter. The filter includes a canister having an open end. An end plate is secured to the canister at the open end and includes an inlet port and an outlet port to provide for fluid communication with a mounting adaptor of an oil circuit. A reactor housing is arranged inside the canister and comprises a bowl and a lid. The reactor housing defines an entrance port and an exit port. An acid neutralizing bed of acid neutralizing particles is deposited in the reactor housing. The acid neutralizing particles comprises primarily of calcium carbonate compound or other suitable medium which may be provided by crushed limestone. A particulate filter is also arranged in the reactor housing between the acid neutralizing bed and the exit port.