I've put a Weiand Stealth alu intake on my -89 318 & carb & waterpump & radiator is new. Now then: every time I go for a drive it overheats after 3 miles & so I refil & then it don't! & I've got a manual switched electric fan on full + the inside heater & fan on full too, but it aint helping a bit. I can go on for 200 miles after refill & no overheating... Just going to work or back home from work means stopping after 3 miles to refill the radiator. If there's a air-pocket or bad ingition timing it shouldn't change after re-fill, right?