INADEQUATE LUBRICATION
This may be due to inadequate oil pump capacity, inadequate oil gallery or oilway diameters, incorrect grooving design, accidental blockage or cessation of oil supply. In the case of machines depending only upon shaft driven lubricating oil pumps, it may be due to inadequate oil supply during starting up - perhaps due to failure to operate hand priming pumps in an adequate manner. Depending upon the duration and severity of the lubrication failure, surface melting and wiping, or complete seizure of the bearing may occur. 

JOURNAL BEARINGS 
Fig. 35 - Fatigue cracking caused by inadequate lubrication due to axial grooving in loaded area. 

Fig. 36 - Overheating and damage of tin aluminium bearing surface due to reduced oil flow caused by sealed cavity with no drain hole at one end of bearing.

Fig. 37 - Seizure of 20% tin aluminium bearing due to lubrication failure.

RECOMMENDED ACTION 
Investigate and, if necessary, correct groove design. Investigate lubrication conditions. Scrap bearings. Examine and, in cases of seizure, crack detect journals. Fit new bearings.