‘High temperature’ is essential to define.

Determining the actual operating and surface temperature of the lubricated surfaces is crucial taking into account any cycling, and extremes. 150°C is a realistic upper limit for hydrocarbon, synthetic PAO and even ester-based lubes, as rates of oxidation double for every 10°C increase above this correlating to lube service life, effectively halving for every 10°C increase. PFPE based oils and greases offer extreme thermal stability with grades capable of running continuously at 300°C as they do not oxidise, burn or form lacquers or tars.