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1971 GT
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638 Posts
Discussion Starter · #1 ·
The last few days have been 36 degrees around here. (That's about 98 F for you folks south of the 49th)

I turned off the stereo in my GT after a drive and it sounded like there was a sprinkler under the hood. Coolant was spraying everywhere. I pulled the rad and flushed it. The hoses were good and when I refilled it, it started a slow leak, so it looks like it has burst somewhere.

The question is, before I invest in a new rad, should I be looking at some underlying problem that could have led to such a build up of pressure? I don't want to blow the new one.
 

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boomerang opeler
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5,670 Posts
is the rad the original for the car if so i think it will just be corroded out , when you put the new 1 on it should be ok but you can make up a pressure gauge with an output gauge from an old welding regulator and a rad cap
if you drill a hole in the cap to match the threads on the gauge and get 2 thin nuts to fit , bolt it together and fit to rad then when you start up it should not go over about 15.2 psi if it does it is a head or gasket problem
 

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Super Moderator
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6,365 Posts
I was able to get both the GT and Ascona rads re-cored here in Calgary, so you should be able to find someone in or near Trail that can do likewise. And ask if they can do a "3-core" as it will greatly improve the cooling system, and likely prevent the recurrence of the "Great Pressure Build-up"

Hmm, that said, is it possible you have a blown head gasket or cracked (GASP!) head? Either can cause combustion pressures to get into the cooling passages, and exacerbate a cooling problem. Kind or ironic, as overheating causes the cracked head in the first place (ask me how I know THIS!)
 

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Premium Member
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1,973 Posts
If the water pump isn't working at an efficiency great enough to safely cool the engine pressure can build up because of hot coolant boiling in the block and possibly turning to steam.
 

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Member
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247 Posts
a quick rad restriction test, with rad out of car, take a garden hose hold it in the top hose connection, turn the water on full, in MOST cases you should not get any water out of the filler neck(where the cap goes). Of course make sure you have the hoses and the cap off. Also when you go to a rad shop ask for a 3 ROW rad core and not a 3core, a radiator only has one core!HTH
dan
 
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