[Neil]

Yes ther will be SOME air movement but mush of it's from the fan which is blowing hot air from the radiator. Take a feel on a warmed up vehicle and see how hot the blast is. Heat only rises. There's a lot coming off of the engine and exhaust manifold. Hey get a small thermometer and attach it to the underside of the hood. Run around for a whil , then check the temp as a test. If you had an open cowl hood, that would greatly help in that area.