Chosen Solution

Is it normal for a intel 2.5 gHz (turbo boost to 3.1gHz) i5 (ivy bridge) in a mid 2012 MacBook Pro 13 inch to get up to 75 degrees C under heavy load?

A little too much for this. You can easily get rid of this problem by replacing thermal paste. How to remove the cooler from here Thermal Paste

First remove the fan and clean out the vent. MacBook Pro 13" Unibody Mid 2012 Fan Replacement If the vent looks clean, look at the heat sink. See if there is an oily looking residue around it. It is liquid filled and can spring a leak and may need to be replaced. MacBook Pro 13" Unibody Mid 2012 Heat Sink Replacement

Whats your temperature now? @col117

100 Celsius is the limit. 75 under heavy load is completely normal. You don’t need to replace your thermal paste. SMH.