Temp loss when fan comes on  

Temp loss when fan comes on

I have read other thread on verrrrry similar issues with clogging. The problem could be heat-creep, but I don't think it is.
Besides, I have had this machine for less than, and do not want to tear it down to put thermal compound on the heat break.
I am going to tell you a series of odd occurrences in hopes of solving my problem. I ordered, received, and assembled my Prusa MK3. It worked perfectly until I used up the first spool of PLA that came with the machine. Then the problems began. Following your instructions, I loaded a new spool of PLA. During my first print, after the reload, the LCD blinked and then displayed garbage for about 2 to 4 seconds, then returned to the normal menu display. My prints started failing. Not every print, but every 3rd or 4th print. The nozzle sometimes clogged. I increased the working temp from 200 degrees to 210 degrees. The clogging seem to almost go away. Then the clogging started within 10 to 20 minutes of any initialing print job. I noticed that when the nozzle fan firsts comes on, the temperature would drop from 210 to 200 degrees. So, after I start a print, I wait for the temp to drop, and immediately tune the temp back up. Now, approximately 3 hours into my prints, the printer stops printing. The display says, “Preheat Nozzel” and the error message log says “Filam runout”, however the filament is till loaded. I have logged 15 days 7hours use on the machine. Any one got a solution? I appreciate any help that is offered, so I'll say Thank you in advance.