it could be your engine fan. at high speeds air is forced into your engine to cool your radiator, but if the fan is broken, when you slow down, no air is ventalating to the radiator, making it get hotter, keep us updated.
it could be your engine fan. at high speeds air is forced into your engine to cool your radiator, but if the fan is broken, when you slow down, no air is ventalating to the radiator, making it get hotter, keep us updated.