Zoiks!! Can't get the 300 V8 in my 64 Special to stop overheating. This only happens on the highway going 60 or 65. For short distances around town, the temp gets a little threatening but never overheats. When you get off the highway, it seems to cool down as you drive at slow speeds. Fine at idle. Engine runs strong, accels well at all speeds. Car has: new water pump new thermostat (installed correctly) good hoses, fresh coolant Other notes: No bubbles in radiator or other signs of head gasket trouble Radiator is hotter in upper-central section. Poor circulation? Wouldn't this be a prob around town? Small tick sound (valve lifter?). Follows pace of engine RPMs. This only appears when car has been sitting for a week or is really hot. Quiets down the rest of the time. Suggestions? Thanks for reading, Michael
Sounds like either there is a restriction somewhere in the system..... system might need flushed, or there might be air trapped in the system. Do you have a direct drive fan or a fan clutch on it? Might be a bad fan clutch, and the fan might be free wheeling. Mike
Ok, I admit, the antifreeze mix may be a little haphazard. The car has some heat, but it's not as hot as the engine temp would make you expect. Since I just got this convertible (or rather, dug it out of a ditch in the Santa Cruz mountains) I don't know how hot it should be. But a clogged heater core doesn't stop the engine coolant from circulating, does it? I thought it was just a loop of circulation off the system. John, you're right, I really should get the timing precise. -Michael
Fan is direct drive, bolted to the water pump. The most recent thing I did was the thermostat, so I figured any air would have slipped out when that was opened up. After installing it, I just filled the system to the top, capped it, and drove around the block. Should I do something else to burp it? -Santa Cruiser
On some cars the heater core always has water flow thru it and is part of normal cooling system--air flow is diverted to turn heat on and off; I don't remember if this is true for 64 S/L?? John
. do you have a overflow bottle ? after filling radiator you need to run till thermostat opens , be sure coolant is flowing , add as needed then cap it up . if a overflow bottle is used, fill that to the proper line.:grin:
Ummm... the overflow reservoir actually isn't connected. The hose fitting on the radiator snapped off.
when you installed the thermostat you said you filled , capped it closed. without a overflow bottle for the system to add or subtract as needed you have to fill , start engine ,watch level , watch flow , put cap on one click , let it idle 10 minutes or so check level. is that cap good , is it the correct cap for car ......................................................................................?? then when full tighten cap .
Possibility of an air lock but after driving at highway speeds that should circulate the coolant and get rid of any air. Is the car actually overheating? If you have a guage it may not be accurate, bad sending unit etc.. If the rad is original there could be enough corrosion build up internally that coolant flow is effected. Good idea to check hoses, especially the lower one. If the hoses are soft they can actually collapse and cut coolant flow to nothing. Lower hoses often have a wire coil inside to prevent collapsing, might be rotted out. Clogged heater core shouldn't be a problem. Newer cars have valves that stop the flow altogether. Good luck.
The level remains steady after driving it. The cap is a proper fit. How do I see if there is good flow? Just by looking at the fluid in the radiator?
Thanks everyone for the suggestions. I am going to tinker with the car for a while. Will check for further insights later. -Michael
A clogged radiator will do this. The heater core sounds like it's clogged, so the radiator could be as well. I had a '72 that overheated on the higway. The radiator was 50% clogged with blue silicon...I couldn't see it at all from the cap, the clogging is all on the other side of the radiator.
flush and fill system...put a new thermostat in. Change the Radiator cap. If your reservoir isn't hooked up, then you need to get it hooked up. You said the fitting on the radiator is broke off...get a new one! You'll save more money buying a radiator than if you warped anything getting it too hot.
This is typical insufficient radiator. Its either too small for the motor(unlikely) or it is clogged (very likely). In any case it can't pass enough heat when your on the highway, but will handle around town driving. I say change the radiator especially if you don't know how long it has been there.
i know the heater core in my skylark is bad, but there is no windo fogging, antifreeze smell, or vapor from the vents unless the heater is turned on...wouldn't this mean the heater core is out of the circuit? in my 82 mustang i had to bypass the heater core to get rid of the antifreeze smell and keep the windshield from fogging, even with the heat off...
