My 68 camaro has a 383 blown small block. Ever since I built it and installed the engine I have had overheating problems. I installed every radiator from alluminum to copper. I have a 4 core copper radiator in now and it will run for about 5-6 miles at about 185. Then slowly it will rise to over 200. I have alluminum heads and dont want to warp them. I am running the largest electric fan all the time. I have removed the thermostate and have tried restricter plates and everything you can imagine. I ran a B cool alluminum radiator and it did nothing. Would a shroud help or maybe two fans.
Check the fan clutch and also could be air in it-try bleeding it and see what happens if it continues -get it block and pressure tested
October, 15, 2011 AT 9:52 PM
I have tested for air pockets. It only has an electric fan. No mechanical. There is no room with the blower for a machanical fan. I have a jeep with a small 2 core radiator and electric fan runing a 350 cu in and have no problem with cooling.
October, 16, 2011 AT 12:13 AM
No shroud? You identified the problem. Without it, the air just goes right back around and comes back in through the radiator after being heated the first time through. Also be sure there's no holes in the core support for air to bypass the radiator. Same with the rubber strip that clips under the front edge of the hood or on top of the core support. That blocks air so it has to go through the radiator.
It is also possible to cause an overheating problem by removing the thermostat. The hot coolant doesn't stay in the radiator long enough to give up its heat. If you have coolant that is too high in antifreeze and not enough water, overheating can result. Antifreeze doesn't hold as many BTUs of heat as does water so it's less effective at transferring heat to the radiator.
Any chance the pulleys are the wrong size and the water pump isn't spinning fast enough?
October, 16, 2011 AT 1:47 AM
I think you are right with the lack of a shroud. I will try that and see what happens. Thanks so much for the tip. I will keep you posted.