First of all, I'll start with the introduction; my name is Allen and I'm 16. I have a 66 coupe with, unfortunately, a 67 289. (I was quite unhappy when I found out.) I'm trying to keep it as close to stock/original as possible. I'll try to get pictures of it on here eventually, but it's painted Silverfrost. I look forward to meeting all of you knowledgable mustang enthusiasts.

Ok, here's my problem. While I was at school, my dad tried to get it running to take it to get the headliner installed. He said that whenever he starts it and lets it run for a minute, coolant/antifreeze pours out of the overflow tube (brand new radiator BTW). We thought we corrected this when we installed an overflow tank. He said that he added more coolant to the radiator and filled the overflow tank. So, today, he said that he tryed it again and coolant filled up the tank and ran out the overflow tank. I was talking to him, and he said that he would try it again with the radiator cap on, so I assume he left it off (don't ask why, I have no clue). We also used the same cap from the previous radiator if anyone needs/cares to know.

I will try to give further details if anyone needs them, but as I was at school, I really have no clue as to what happened. We are not car people, just restoring the car as a father-son project since we both love mustangs. I greatly appreciate any advice and suggestions on the matter. Thanks in advance.

 

It could be a number of things I would say start with the thermostat could be stuck or installed backwards, waterpump could be bad, or air in the system.

 

Do not fill the overflow tank. It only gets filled about 1/4 of the way. Yes, put the 13 lb. cap on the radiatior. Did you change the thermostat? Your radiator needs to be burped. You have trapped air in it that needs to get out. Make sure the overflow tank is only 1/4 full, and drive the car so that all the air is expunged from the system. Get it hot. Stop it. Let it cool. Get it hot. Stop it. Let it cool.,,,,,etc. etc.

 

I was told to use 7 lb cap. But then again I have a 65 with a rebuilt 302 if that makes a difference. I'd just take it to the radiator shop.

 

just hope its a air bubble thats the easiest fix most auto parts store sell a pump you pressure test the coolant system with works great at removing air bubbles

 

Thanks for all the help. I didn't think that you were supposed to fill the overflow tank up, I thought that that was the point of it in the first place. I will surely try everything you guys mentioned, and once again, thank you all for your support.

 

its always good to see younger guys taking interest in classic muscle. ricers suck!

 

My guess is the thermostat. Not a hard fix, just make sure you don't overheat that motor...

 

fella says tyhat it's bubling in and out the radiator.
If the thermostat is broken it won't open and the water in the radiator should
- not warm up (motor yes, radiator no)
- not move. so I can't explain how it shoots out when the way from engine to radiator is blocked.

so from this I rather guess as well there are air bubbles in the system

kalli

 

Nah, a 7 lb. cap would be worthless. These cars use a 13 pounder. And, forget about the thermostat. Get the air out of the system.