Topic: 1966 Mustang overheating

[arojo1972]

I have a 1966 Mustang with a 302 '68 V8 engine and it overheats.  The car has a high volume Edelbrock Aluminum pump, with a double rolling timing chain,  4 row aluminum radiator from summit, electric fan 16 pull.  The car was sitting for a few years before I bought it.  It has some aftermarket parts for example Unilite Mallory distributor, a Holley 4barrel carburator.  I took the water pump off and it seems to be good but I'm not sure, my friend the mechanic says it's good because it's pumping water.  So then I put it back on and I took the radiator out and flushed it with water and I put it back and the overheating continued.  you drive it like 20 mins and it starts to overheat.  Then I took the heads and took them to a machine shop to be inspected and they were fine so I put them back on with new gaskets everywhere and they were correctly installed.  Seems like the engine is really clean in the inside, like somebody worked in it before, which I like it. It has Shelby springs in the valves.  Took the radiator out again because the top hose was getting stiff like before then I took it to a radiator shop and they flushed it, put it back on and refilled the radiator with anti-freeze and it went down better.  I saw the difference in the temperature, I took it for a drive a few times, short trips and when I got back home the temperature was at like 3/4 between the cold and hot.  When it cooled off I took the top off  the radiator and there were residuals (like tiny rocks/sand) like before I flushed it, then I disconnected the hosed and flushed it again with the water hose, put it back on and it was working at some point satisfactory and after a few short trips it started to overheat again.  Lastly I took it to Jiffy Lube and they flushed it, I thought it was going to work but it made it worse, like in the beginning.

Any advise on how I can fix this?  Do I need a new radiator because it didn't move for so long, or a mechanic fan versus electric fan?  Or because the top hose is getting so stiff, do I need a new water pump even though my mechanic says it's good?

Thank You!!

[thundertc64]

I would start at the easiest route and try a different thermostat , also what is the idle speed of engine . Had a 93 T-bird that would run hot constantly did all the usual checks ,but over looked one minor detail that the idle speed was a tad bit high and  the water was circulating to fast to cool down , i would also check to see that the electric fan is actually coming on at the right temp

[Jeff73Mach1]

and when you say overheating are you relying on the gauges alone (Which could have a bad sending unit or ground) or is it puking coolant?

50-50 mix of water antifreeze cools better than straight antifreeze

[Topless_Horse]

You say that your top radiator hose was getting stiff.  Do you, by chance, have a large spring in the lower hose?  If you don't it may be collapsing, which will restrict water flow through your engine and radiator

[Jeff1967]

If you don't already have one, look into a fan shroud.

JJ

[Bill Reeves]

My Mustang ran hot because I set the timing before the car was properly warmed up, so when it did warm up, the timing was too high.