Q: My Mac Becomes very hot easily and fan keeps running even without running any apps

What happens if you shut down Safari?

Run an Apple Hardware Test:

https://support.apple.com/en-us/HT201257

Note that an error free AHT is not definitive.

Ciao.

Back up all data before proceeding.

Quit Safari if it’s running. Then select

           ▹ Force Quit…

from the menu bar. A small window will open with a list of running applications. Safari may appear in that list, even though you quit it. If so, select it and press return. Close the window.

Step 1

Hold down the option key and select

          Go ▹ Library

from the Finder menu bar. Delete the following items from the Library folder (some may not exist):

          Caches/com.apple.Safari

          Caches/com.apple.Safari.SearchHelper

          Caches/com.apple.SafariServices

          Caches/com.apple.WebKit.PluginProcess

          Caches/com.apple.WebProcess

          Caches/Metadata/Safari

          Preferences/com.apple.WebKit.PluginHost.plist

          Preferences/com.apple.WebKit.PluginProcess.plist

          Saved Application State/com.apple.Safari.savedState

Leave the Library folder open. Try Safari again. If the problem is solved, stop here. Close the Library folder. If you still have a problem, continue.

Step 2

Move the following items from the open Library folder to the Desktop (again, some may not exist):

          Cookies/Cookies.binarycookies

          Internet Plug-Ins

          Preferences/ByHost/com.apple.Safari.*.plist

          Preferences/com.apple.Safari.Extensions.plist

          Preferences/com.apple.Safari.LSSharedFileList.plist

          Preferences/com.apple.Safari.plist

          Preferences/com.apple.WebFoundation.plist

          PubSub/Database

          Safari

          SyncedPreferences/com.apple.Safari.plist

Here, "*" stands for a long string of letters, numbers, and dashes.

Note 1: You are not moving the Safari application. You’re moving a folder named “Safari.”

Note 2: This step will remove your Safari extensions, if any, and their settings. If you choose to reinstall them, do so one at a time, testing each time to make sure you haven’t restored the problem.

Try again. Your settings and bookmarks will be lost. The default set of bookmarks will be restored. Delete them all.

If Safari is now working normally (apart from the lost settings), look inside the “Safari” folder on the Desktop for a file named “Bookmarks.plist”. Select

          File ▹ Import Bookmarks...

from the Safari menu bar. Import from that file. Recreate the rest of your Safari settings. You can then delete the items you moved to the Desktop.

If the issue is still not resolved, quit Safari again and put all the items you moved to the Desktop back where they were, overwriting the newer ones that may have been created in their place. You don’t need to replace the files you deleted in Step 1. Stop here and post again.

If you don’t like the results of the last step, you can undo it completely by quitting Safari and restoring the items you moved or deleted in that step from your backup, overwriting any that were created in their place.

I just encountered the same issue.

Eventually a post somewhere on MacRumors forum triggered a thought. Just hours ago Silverlight had asked me to update. Update is good, right? so I did update.

Thinking of that, hearing the fans roar, feeling the laptop burn in my lap I went ahead and kicked Silverlight into the trash can.

Voilà! - Fans are quiet, my old workhorse as cool as ever...

Dear M$ with all your new and shiny Office Suite, you almost had me fooled :-)

So, if your baby is running a high fever and complains about Safari sucking energy, head over to /Library/Intern Plug-Ins and kick out Silverlight and everything else you don't seem to need or don't like.