crazyshuffle

So my 65 mustang fastback 289 is having overheating issue and I have replaced thermostat and flushed radiator yearly. It has an electric fan,but after driving recently the Radiator leaked out way too much. I checked and it come out of the overflow, so I guess this means it overheated. I only drove it around 10 miles.
So any ideas on the best STOCK looking Radiator?? I know aluminum is great but my car is Stock so I want a Black radiator.

Thanks for all the help guys.

barnett468

what heads are on it?

what cam is in it?

are your pistons flat top or dished?

does it run hot since you retarded the timing or just because the weather is hot?

how hot does it run?

hot in traffic or on highway or both?

do you have a fan shroud?

how many blades on fan?

is fan fixed or on a clutch?

what is your thermostat rated at?

air conditioning?

do you use it?

how many rows deep is your rad?

how thick is the core?

how far is the engine bored.

a brass 3 row high efficiency rad usually foes it for most cars.

they sometimes need the dual or tripple pass feature.

crazyshuffle

I know it has GT40P heads, motor runs good. If i don't drive it takes a while to crank but doesn't smoke.Not sure about pistons or cam. When it runs hot it usually driven late in the day when its cooled off some. The factory temp gauge doesn't show its running hot,just shows under half way. My electric fan usually only comes on after driven. When I got the new thermostat I think I got a 180 degree. Radiator is stock. I was told engine is 289,don't know if it was bored but the heads were updated GT40P. NO A/C but I have a unit just not installed. I only drive about once a month,but gonna start driving more often. Don't know about timing,i haven't changed anything since buying it 4 or 5 yrs ago. My first old car, so I have a Mustang mechanic in my town and he works on it if there is anything needed.

racer_dave

If it didn't overheat before, and it is overheating now, what changed? Did you change plugs/timing/tune up? antifreeze brand? When was the last time the current radiator was cleaned by a shop? Is the electric fan a new addition or was it that way before?

First thing I'd do is make sure the electric fan is coming on when it should. Second I would swap the electric fan for a mechanical fan and see if it changes. Not that electric fans are bad, this is just an easy place to start.

dodgestang

Does it have a catch can?

If you are talking simply about fluid coming out the drop hose straight from the radiator...that just means it was a warmer than its been....but not necessarily overheating.

racer_dave

Hmmm. a basic thing to check- how old is the radiator cap? If it's old then it may not be holding pressure which would allow water out and it would overheat pretty easily.

barnett468

hi . . we need the exact radiator info i asked for . . with no timing specs or exact temp we have no idea. . it makes no sens it runs cool when it is hot out but hot in the afternon when it gets cool. .you need 1 1/4 inch of air space in your rad or it will overflow . . your rad cap might be bad . . what is it rated at . . a 14 should be fine you should put in a 192 stant brand t stat. .

barnett468

if it only runs hot at idle or low speed you need a fan that moves more air.

1966fastbach

I have a 1966 Fastback, 331 Stroker and my inlet at top of radiator and bottom outlet were both on the same side. my radiator guy told me i wasn't using all of the radiator. he switched the top inlet to the other side so they were opposite and told me to use a 185 thermostat. even in 100 degree weather at idle it never goes over 190 F.

crazyshuffle

Hopefully, it was hot that day it drained out more fluid. Gonna drive it friday evening some more and see whats happening because I haven't changed anything on the car and had the radiator serviced or flushed not too long ago.
The radiator Cap is old, it looks rusty color under neath but they added some type of radiator additive that was rust color. This is the fist time it's leaked so I'm going to drive it a few more times and see what happens.