I have a 2000 Jeep Cherokee RHD I bought the Jeep in November 2005 I deliver mail with it, about 6 months ago I had to replace the radiator ( special raditor because it's RHD), now Jeep runs hot have replaced thermostat twice it runs at 210 then fan kicks on but when I start it with the fan running the truck bogs down and I have to wait a few minutes for it to gather it self after that it runs fine again till it starts all over again, mechanic said it's because I'm stop and go and it's not getting air to cool itself but it didn't do it before...HELP!!!!