Where are you seeing these warnings relating to possible excessive heat?
Is the room where your computer's located getting warmer than normal? Summer weather making things hotter?
Whilst you've got the case open, check that all the fans are revolving properly, and that includes CPU fan, PSU fan, and all case fans.
Vacuum cleaner nozzles are renowned for getting a nice static charge building up on them - this is where problems can occur if the necessary precautions aren't taken. I presonally prefer to use a small paint spray compressor to blow dust and dirt out of heatsinks, computer cases, etc.
ROGER - G0AOZ.