After assembling the short engines and truck heads, special thermal indicators are glued to certain places. Thermal indicators are useful because they can tell us what temperature has been reached in certain parts of the engine wall. This is especially important if, after repairing the engine for a short period of time, for example, the pistons, bearings, etc. become seized.

Thermo indicators have five gray "boxes" on them, each of which represents a temperature value of 88 - 131 ° C and if a certain temperature is reached, the gray "box" turns black.