We recommend the use of grease, particularly for automotive applications. The mineral grease is used to coat the journal and to hold the piece of Plastigauge in position. The silicone grease should be applied to the surface of the shell to prevent the deformed Plastigauge strip from dislodging or breaking apart when the two surfaces are re-opened. These steps make it easier for the user to take their measurement using the gauge card provided.
Silicone & Mineral grease – recommended
3g mineral grease:: To coat journal prior to use of Plastigauge
3g silicone grease:: To apply to surface of shell
Lubricants to assist with the measurement of clearance in automotive bearings