Cummins ISX11.9 CM2250 – Service Manual 007-014   Lubricating Oil Filter Bypass Valve

When the pressure drop across the lubricating oil filter exceeds 757 kPa [110 psi], the oil filter bypass valve opens and allows lubricating oil to bypass the lubricating oil filter.

This condition can occur during cold ambient (cold lubricating oil) engine start-ups.

The purpose of the bypass valve is to maintain lubricating oil flow to the engine and prevent an oil filter collapse.

WARNING  To reduce the possibility of personal injury, avoid direct contact of hot oil with your skin.

WARNING  Some state and federal agencies have determined that used engine oil can be carcinogenic and cause reproductive toxicity. Avoid inhalation of vapors, ingestion, and prolonged contact with used engine oil. If not reused, dispose of in accordance with local environmental regulations.

Remove the retaining plug (1), spring (2), and plunger (3) from the lubricating oil cooler housing (4).

WARNING  When using a steam cleaner, wear safety glasses or a face shield, as well as protective clothing. Hot steam can cause serious personal injury.

WARNING  When using solvents, acids, or alkaline materials for cleaning, follow the manufacturer’s recommendations for use. Wear goggles and protective clothing to avoid personal injury.

WARNING  Wear appropriate eye and face protection when using compressed air. Flying debris and dirt can cause bodily injury.

Clean the spring, plunger, and retaining plug with solvent.

Dry with compressed air.

Inspect the o-ring on the retaining plug for cuts or tears.

Replace the o-ring if damaged.

Use a spring compression tester, Part Number 3375182, to measure the relief valve spring tension.

Compress the spring to 28.1 mm [1.11in] height. The force required to compress the spring must meet the following specification.

Force Required to Compress Spring to 28.1 mm [1.11 in]

If the spring does not meet this specification, it must be replaced.

CAUTION  The notched end of the bypass valve (3) must be installed toward the spring (2). If the bypass valve is installed incorrectly, oil will bypass the filter continuously which can cause engine damage.

Lubricate all pieces and the o-ring seal.

Install the plunger (3) with the notched end toward the spring into the lubricating oil cooler housing (4).

Install the spring (2) and retaining plug (1) into the lubricating oil cooler housing (4).

Tighten the retaining plug.

Prime the lubricating oil system. Refer to Procedure 007-037 in Section 7.

Operate the engine to normal operating temperature and check for leaks.