Cummins ISF3.8 Crankshaft Front Oil Seal Replacement

Replacement of the crankshaft seals of the Cummins ISF3.8 engine

The crankshaft seals are replaced when a severe oil leak occurs.

Before replacing the seals, it is necessary to make sure that the oil leak is not caused by increased pressure in the engine crankcase due to a blocked crankcase ventilation system.

Replacement of the front crankshaft seal

The front crankshaft seal is conveniently removed and installed using puller No. 4919660. In this case the front engine cover does not need to be removed.

Puller for the front crankshaft seal No. 4919660
Fig. 1. Puller No. 4919660: 1 — adjusting nut; 2 — washer; 3 — screw; 4 — drift; 5 — adjusting nut; 6 — screw; 7 — adapter; 8 — seal puller.
  1. We prepare the seal for installation of the puller.
Preparing the seal
Fig. 2. Preparing the seal for installation of the puller.
  1. We take an extension from the tool kit and carefully press the seal in so that a gap of 1–2 mm forms between the housings.
Pressing the seal in
Fig. 3. Pressing the seal in to form a gap.
  1. We assemble the puller.
Assembling the puller
Fig. 4. Assembling the puller.
  1. We install the puller into the gap previously formed between the inner and outer housings.
Installing the puller into the gap
Fig. 5. Installing the puller into the gap between the seal housings.
  1. We remove the seal by turning the screw clockwise (the tightening torque of 45 N·m must not be exceeded).

Installation of the front crankshaft seal

Installing the adapter
Fig. 6. Installing the adapter on the crankshaft end.
  1. We install adapter 7 on the crankshaft end.
  2. We screw in two screws M12×1.25×60 mm.
  3. We install the new crankshaft seal on the crankshaft nose and push it into the cover as far as possible.
Installing the drift
Fig. 7. Installing the drift on the screw.
  1. We install the drift (4) on the screw (6) and slide it forward as far as it will go.
  2. We install the washer (2) and screw the nut (1) onto the screw (6).
Pressing the seal in
Fig. 8. Pressing the seal into the cover.
  1. Holding the drift (4), we tighten the nut clockwise until the seal is installed in the cover.
  2. We remove the tool.

Note: of course, there is a simpler method, which we covered for the Cummins ISF2.8 engine (article — Replacing crankshaft seals Cummins ISF2.8).