got a 351 cleveland with 2v heads and an edelbrock 4v intake and a holley 600 carb. engine was rebuilt by a local shop with the heads resurfaced and ported and new springs and rockers and pushrods. it had the old 20 in. radiator and the car would slowly heat. figured the extra power was causing this, so i bought a 24 in aluminum radiator. there is absolutely no difference. it still gradually becomes overheated. at whits end. any ideas at all?
i was told by a local machinist that the head gaskets are probably installed wrong making it only cool part of the block. so that is my next project. that should at least make it able to go down the road. a shroud will probably come later.
1.) Try a different thermostat! If its one of those el-cheapo's from Oreilly's it probably bad... I have seen it time and time again from these parts stores, new parts imported from who knows where with a life expectancy of 24 hours!!
2.) Flush, Flush, Flush. (with plain water) Could be some left-over machined gunk plugging up some passages
3.) Air Purge the system...
4.) The engine could be running hotter in which case a shroud would help pull cooler air...
You absolutely DO need a fan shroud. Without a shroud, what is there to keep the air flowing properly through the radiator?
Also, check to make sure that when you filled the radiator you did not leave any air in the system. It may be helpful to install a bleeder setup in there to help get all of the air out of the system.
i did cut the lower hose with the fan belt after a few minutes of driving but even before then with it sitting it started to overheat, as well as through town and on the open highway. all while being full with water. it wasnt til after several minutes til i cut the hose because of all the moving of the engine and car.
no leaks. it heats at all speeds. idle and at speed.
The obvious question is, have you noticed any leaks lately? And is it overheating at high speeds, low speeds or when you are at a stop/sitting idle?
no, i have no shroud, but it shouldnt be necessary, and there is a wire in the hose. but i just called a machine shop and you were on the right track about the thermostats. there is a brand new one i put there. but they said on a cleveland there should be a restrictor plate beneath them with a half inch hole drilled in it, and if it isnt there the engine will heat right up because the water is moving too fast.
do you have a fan shroud on the car?if not air could flow away from fan causing a dead air spot when not moving fast enough .another possibilty is that if your radiator hoses are not reniforced with wire the lower hose could be sucking shut not letting water flow..be sure to have a thermostat in car so water dose not flow to fast to cool. .
