Why Am I Overheating!!!!!

7374 said
thanks to all so far for the great trouble shooting ideas. i tried to answer your "did you's" and "try this" as best i could. with this information does this change anyone's thoughts or add anymore ideas?

was thinking about the air lock thing. how can i make sure of that?

no springs in hoses, never had them, car ran perfect before.

ran with cap off, coolant is swirling around, car still reached about 230 in 15 minutes of idling. then boiled over when shut off.

not sure about fuel mixture or oil pressure. no pressure gauge, just oil light. using brand new 16lb cap but doesn't seem like pressure is building becuase when engine is hot i can open rad cap to first stop and no pressure is bled off and top hose is soft as can be but hot.

i know the engine is running hot because of a new temp sending unit and the factory temp gauge is at about 230 degrees. the coolant will over flow and is DAMN hot. it takes only about 15 minutes in the driveway at idle to reach this. or a quick 5 mile run. same problem existed with 2 thermostats, so i eliminated to check flow.

I've heard about a half dozen people mention about an air lock so i really want to pursue this but how would i do it? run with cap off? i filled the block through the top radiator hose with no thermostat, then topped off the rad after reconnecting hose.

ugggghhhh!!!!!!!

Hi Guy's

I'm new to the forum. I had overheating issues with my 69 swinger 340. I tried everything I could think of. I have a aluminum cross flow radiator, a steel 7 blade fan with a shroud, an electric pusher fan on the other side of the rad, a Brass Works high flow water pump, tried removing thermostat then replaced with a flow restictor, installed a transmission/engine oil cooler (the transmission fluid does not go through the rad) and STILL I couldn't keep the engine from overheating when I got stuck in traffic. The temp was fine when I was moving in fact it was a little too cool (170 degrees I'll have to re-install the thermostat). In frustration I installed a second aluminum rad and had it idling in my driveway at 170 degrees for over 20 minutes. I decided to take if for a test drive so I put my fiberglass six pack scooped hood back on the car. By the time I came back down to the garage after washing my hands the temp gauge had climbed to 195 degrees!!!! I was dumbfounded. My buddy and I started checking and you guys won't believe what we found. Because I have the fiberglass lift off hood it doesn't have the rubber strip that is normally attached to the underside of the hood and seals to the rad support. The hot air was comming out from under my hood and was being sucked back through the rad, heated up and then out from under my hood then heated again, the sucked ba......well you guy's get the picture. I temporarily used a piece of foam pipe insullation and fasteded it to the rad support with zip ties. Car now idles in traffic at about 190 degrees on a 85 degree day. I hope this helps some of you guys. Great Forum!!!!