mine as well as several others I have talked to , are plagued with constant overheating issues, resulting in blown headgaskets… and clutch/trans issues .. Massimo admitted to me in email that these 500 and 700 HISUN engines were not good and they discontinued them, went to another Chinese Company for engines .. But refuse to help any of us that were dumb enough to buy them.. I bought mine in 2018 new.. its been in shop 5 times , only has 300 miles.. I hope you have better luck. ….oh, and its in the shop right now.... HEAD GASKET