Cummins/Onan — Check Turbocharger Bearing Clearances
Testing & diagnosis
From a Cummins/Onan service manual covering: V12 Series, V6-140, V6-200, V6-VAL, V6-VIM, V8-185, V8-265, V8-350, V8-VALE, V8-VINE, VT12, VT8-430. Check it applies to your exact model before use.
Applies to: Cummins/Onan V12 Series
Before you start
- If end clearance exceeds limits, remove turbocharger from engine and replace with new or rebuilt unit.
Procedure
- Remove exhaust and intake piping from turbocharger to expose ends of rotor assembly.
- Remove one capscrew from front plate and install a long capscrew; attach indicator.
- Register indicator point on flat of rotor shaft; push shaft side to side and note total reading.
- Move indicator point to end of shaft and check end-play.
- Check radial clearance on compressor wheel only.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Limits in Table VI (minimum figures)
Full service-parts list: Cummins/Onan V12 Series →
Source: Cummins/Onan service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.