[mautemps]

Hey there, so I rebuilt this 1978 302 and dropped it in with 351 heads and a 650 holley. Got it timed to the mark (6BTC) Here's the thing. It overheats like crazy. past 230 easy. I pulled the heads off this morning just to make sure I put the head gaskets on correctly which they were. I put on a different waterpump which I am sure works, I even pulled the thermostat, Just for the summer (gets hot in the city sitting in traffic) But I still cant figure out what the heck is going on. I even have the heater going and that does nothing. I'm using the same water pump that was on my 351, which was new when I tore that engine down. I even threw on a 10,000 rpm rated 17 inch flex fan. Now the only thing I can think of is the radiator. This came out of an eliminator that my friend sold a few years ago, doesnt leak or anything, but I dont want to drop another 200 bucks on a radiator unless I know thats what it is. Is there a certain way to fill the radiator or something on these older cars. I dont know, but any suggestions would be greatly appreciated being this is the only thing that is stopping me from ripping up the asphault in brooklyn. Thanks

 

[modifiedmark]

Sounds like you got all the bases covered. Pull the radiator and have a shop look it over for you, they useally dont charge to look it over and it maybe your problem. mm

 

[bowl]

Is the fan shroud in place?
Try using more water (distilled) than antifreeze.
Antifreeze runs hotter than water. I used to run all water and one pint of antifreeze in my 67 289. I would put the thermostat back in so the water is in the readiator long enough to cool. check the thermostat by dropping it in a bowl of hot water (180°F or hotter)to see if it opens. Be sure the carb is not running too lean. is the water circulating good, you can see it move with the cap off. verify the water temp with a mechanics thermometer or equal.

 

[mautemps]

Naa, I think the radiator is bad. When I use the Prestone Backflush system its stays cool with no problem, and the water circulates fine, but when I close it up, It iver heats. Seems like the water isnt circulating through the cooling fins. I think it might be time to vite the bullet and get a radiator.

 

[72cat]

We had a similar problem with out Sierra, [C3 at] tried everything, just kept overheating, even got the radiator recored, twice, eventually we discovered that the AT oil cooler/heater for the AT pipes was stuffed, and altho they had recored the radiator, they did not check the oil thing out, got that fixed and problem was solved, don't know if that is of any help to you, but its a thought.

 

[Tim B]

I had my radiator recored awhile ago. I went with a three core. They can be just as effective (or better) than a four core if they are done right. I kept the top and bottom of the radiator with all the original Ford stampings so it looks original. By luck I went to an old timer who really knew what he was doing. I have the factory style clutch fan and radiator shroud with a 428CJ C6 and a trans cooler. FEs are notorious for overheating, especially if bored out on a rebuild. The only thing that overheated was me! I had the top down and my brain was fried by the time I got to the Nats. LOL

Even in BADDDDD L.A. rush hour traffic going 0-20 mph it was only 1/2 or less on the temp gauge! It was about 2/3 doing 85mph.

One time a long time ago a detailing shop put the thermostat in backwards on a 64 Falcon......It overheated big time!

Tim B
1969 XR7 428 CJR convertible
http://hometown.aol.com/timbrands/Cougar.html