Code 41 on new motor

We purchased an 05 eS with less than 5k on it. Had some problems, mechanics, etc. The motor was a standard and our neighborhood is hilly. We “could” make it up some streets with a run at it.
Good Guy “Bob” gave advise, loaned us a motor temp., and we put a 7.5 in it which makes it work fine. We notice that we get a code 41 again if we drive it 3 or 4 miles.
Would an electric fan help?

If you need to cool the motor I saw a guy on you tube that made a heat sink for his 7.5 Hp motor here is a link to the video
[ame=]GEM Car “GE Motor Heat Sink” - YouTube[/ame]