325D and 329D Excavators Hydraulic System Oil Level - Check Caterpillar

Hydraulic System Oil Level - Check

------ WARNING! ------

Hot oil and hot components can cause personal injury. Do not allow hot oil or hot components to contact skin.


Never remove the fill/vent plug from the hydraulic tank if the oil is hot.

Air can enter the system and cause pump damage.

Illustration 1g00102817
The hydraulic oil tank is on the right side of the machine.

  1. Park the machine on level ground. Lower the bucket to the ground with the stick in a vertical position, as shown.

    Illustration 2g00102818

  2. Open the access door on the right side of the machine.

    Illustration 3g01121278
    (A) High temperature range
    (B) Low temperature range

  3. For a cold machine, maintain the hydraulic oil level in the low temperature range (B). For a machine that is at normal operating temperature, maintain the hydraulic oil level in the high temperature range (A).

  4. Close the access door.

    Illustration 4g01208340

    Note: Refer to Operation and Maintenance Manual, "General Hazard Information" for information that pertains to Containing Fluid Spillage.

    Note: Perform Step 5 through Step 7 if the oil level is low.

  5. Slowly loosen the fill/vent plug in order to relieve any pressure. Add oil, if necessary. See Operation and Maintenance, "Lubricant Viscosities".

  6. Check the O-ring seal of the fill/vent plug. Replace the O-ring seal if the O-ring seal is damaged.

  7. Clean the fill/vent plug and install the fill/vent plug.