"Walking Crank" (1995-1999 turbo)

This problem involves the crank bearings on 4G63 (the turbo motor) engines in 1995-1999 cars. The problem seems to be that excess play in the crank bearings can cause the crank to travel ("walk") back and forth along its axis of rotation in the block, eventually wearing out the bearing housings and potentially damaging the block itself. (That's bad.)

The biggest indicator that you might have this problem is a clutch pedal that stays stuck to the floor, especially after making left hand turns. (The crank slides over and the flywheel slides away from the clutch, so the clutch won't engage...). If the play in the crank becomes bad enough, it breaks the crank angle sensor off the end of the crank, and the motor shuts down completely.

"Crank walk" is often mis-diagnosed by dealer technicians. We've heard of car owners replacing multiple clutches trying to fix a clutch problem, when the problem was really crank bearing wear.

This seems to be an increasingly common problem on the 95-99 turbo DSM's. We have heard firsthand of dozens of cases, and online reports seem to suggest that the numbers are in the many hundreds.

There are several theories about why this happens, including bad crank machining, oiling problems at the bearings, and excessive bearing cap tolerance. So far, no theory is proven, since the problem takes years to show up, and none of the possible solutions have been in place for that long.

If you have had this happen to you, or if you have worked on a car that has this problem, drop us a note.