Faq

Frequently Asked Questions (FAQs)

1) What is Viscosity of Oil?

Viscosity of oil is a relative thickness that determines the flowability of the oil.

2) What is Flash Point of Oil?

Flash Point of oil is the temperature at which the oil starts generating enough vapors to ignite the oil in presence of an external source.

3) The colour of the oil has changed within short duration of putting it in application. Should I throw away the oil as the quality does not seem to be OK?

There are few additives incorporated in few types of oils (more common in case of gear oils) that change the colour due to change in the surface chemistry immediately (or within short duration) on coming in contact with rotating surfaces (dynamic load condition). This change is colour is within the known behaviour of the oil and does not affect the performance of the oil adversely (or in any other manner). In the case of engine oils, it turns dark on usage due to the detergency characteristics of the oil .

4) What is the best place to draw sample of oil for further testing and analysis?

The best place to draw a sample of oil is from the downstream of an any application. Ideally one should draw as many samples as possible so as to get the most accurate analysis done. e.g. For large lubricating or gear oil systems, draw the sample from the oil in circulation and from the bottom of the sump / reservoir. In hydraulic systems, draw a sample from the header tank, downstream of filters etc.

5) What is penetration of grease?

Penetration of grease is the relative thickness of the grease also known as consistency of the grease.

6) How much grease should be used in a bearing during assembly?

It is recommended to only fill half of the free space of an antifriction bearing. As an exception, for low speed and highly dust prone application, one may fill upto 100% free space in the bearing. Please note that over - filling of the bearing leads to more failure of the bearings as compared to under - filling of the bearings.

7) How do I determine the service temperature range of grease?

The upper service temperature is determined by ascertaining the evaporation loss and the thermal stability of the base oil, dropping point of the grease and the maximum serviceable temperature of the additives incorporated. The lower service temperature is ascertained by testing the low temperature torque of the grease and pour point of the base fluid. The temperature range indicated in the product bulletin is only meant to be an indicator for the actual use. The real temperature range should be determined by considering other factors like operating condition, atmosphere and type of application.

8) The colour of the grease has changed within short duration of putting it in application. Should I throw away the grease as the quality does not seem to be OK?

NO. There are few additives incorporated in few types of grease that change the colour due to change in the surface chemistry immediately (or within short duration) on coming in contact with rotating surfaces (dynamic load condition). This change is colour is within the known behaviour of the grease and does not affect the performance of the grease adversely (or in any other manner). You may continue to use the grease till its intended life.

9) Is it common to observe oil separation in greases?

"Bleeding" or Oil separation is a naturally occurring phenomenon and should not be construed as a problem. The storage temperature in excess of 45 deg C accelerates oil separation. The excess oil can be safely stirred back into the grease within the container. It has also been observed that the higher penetration greases (Lower Consistency) tend to have more oil bleeding as compared to thicker greases.

10) The colour of grease has become darker as compared to when i first opened the container. Should i throw away the grease?

No. It is perfectly alright to use the grease. Few greases (and oils) contain additives that darken by exposure to sunlight, air, temperature. The colour would usually change to slightly darker shade (darker brown in most cases). Sufficient care has been taken to ensure that this change in colour has no effect on the performance of the product. The colour of the grease also depends on the colour of the heavier base oils used.