So I had the 64 Dynamic in the Charlotte St. Patrick's parade yesterday. At the end of the parade, I emptied out the riders and noticed steam coming out the grill. No hot light appeared on the dash but visually steam was escaping under the cap and out the front of my original 6 Harrison.

Without the light appearing, where should I be concentrating my repair? Thermostat? Water pump? Anyone rebuilding and sealing these Harrison radiators in SE USA?

 

I can pretty much guarantee that the water pump is NOT the problem. Think about it. The pump has an impeller that is turned by the fan belt. Unless the impeller has sheared off (which is EXTREMELY unlikely, though not completely impossible), that is NOT your problem. There are no other reasonable failure modes of the pump that can cause overheating. Start with the easiest things first. When did you last replace the radiator cap? Does this car have a clutch fan or a fixed fan? If a clutch, do you know it's working? When was the last time you flushed the cooling system?

 

How much coolant have you lost? If steam was coming from the cap, it needs to be replaced for starters. From the grill, you need to inspect the complete outer rad unless it was runoff from the cap side.
This is what I would do,
1) Be sure all the belts are tight, fan/clutch are in good condition. Put a catch can under the car by the filler neck.
1)Remove the rad cap check the inner tubes for build-up around them. Inspect the rad tanks for cracks, seam leaks, and then core leaks. If leaking you will notice wet spots or darker spots where the antifreeze has dried.
2) Purchase some new antifreeze, thermostat, silicone, gasket and rad cap. ( Since it has overheated somewhat )
3) Prior to draining the system, just top the rad off with water initially, leave the cap off, run the engine at 1200 RPM for at least 15 min with the heat on at full (defrost)
You should begin to see flow through the tubes within 10 min or so, increase the RPM to 1800 RPM, the flow should increase dramatically and begin to purge out the filler neck.
4) Once coolant begins to purge from the filler neck, bring the RPM down slowly to Idle, allow the rad to purge itself while at idle, put the cap on , shut the car off let it cool.
5) Report back, many here will assist further .

Hope this helps to get things started for further diagnosis.
Eric

 

Recheck the timing. If the timing gear has lost teeth, it may be a jump In timing. It may call for changing out your timing chain and gears. Just a thought.

 

Huh?