High pressure in radiator?

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JefftheComputerMan

JefftheComputerMan

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I have a 64 Valiant with a 318 (purchased from ebay little know about the setup). Pretty mild cam, and have no idea on water pump that is on it. It seems to pop a new leak on the cooling system every day! mostly on tlhe radiator, it looks to be the slant 6 original.

Should I go with a 2 or 3 core aluminum for a replacement?

The thermostat seems to open at 180 and stays cool until I sit at a red light, then it can climb up to 220 pretty quick (5 min or so). I live in Texas and it's currently in the mid 50's - 60's most of the time.

What the hell is going to happen when it hits 100 degrees outside?

I upped the radiator cap to 18 lbs from 13 lbs. Did I screw up? Is the water pump pushing too much?

I'm afraid if I replace the radiator I will have blown hoses or worse? Am I crazy to be afraid of the pressure generated here?

What is the "average" or normal pressure on a cooling system?:newb:
 
Fan shroud?? As to the leaks probably be best to just replace the radiator.
 
Any good system should hold the highest PSI cap you can buy

Pressure is NOT caused by the water pump

What causes pressure is heat of the engine, or UNWANTED pressure entering the system from a blown head gasket, or an oil passage leaking into the radiator.

Too much heat/ running hot has many causes

Dirty/ plugged block or radiator, damaged water pump, retarded timing, too small rad, not enough fan or shroud, bad/ late thermostat,

Once back when I owned the black 426 '64, it started overheating at slow speeds, was fine over about 40. I had it apart twice, was tearing my hair out Pulled the water pump AND JUST HAPPENED to stumble over it with my big fat feet. IT RATTLED!!! A quick look, and the stamped steel impeller had rusted loose from the pump shaft.
 
That radiator should be replaced since you say it keeps springing a leak and it very well could be the reason for it overheating. Before changing it out thought I would fire it up for a bit and feel the rad. for any cold spots. Easiest low buck way I know to check for a blockage. You should still verify though that the stat opens and the pump is working.

As far as what radiator to get it depends on the specifics. You could get a 2 core that may work better than a 3 core. It depends on the tube size. 3 cores @ 1/2'' wide will be outcooled by a 2 core rad. with 1" wide tubes. The one in my car I looked up for a newer model ac equiped car. (I believe it was a 71 or 72 a-body radiator) Cools just fine year round and I too live in Texas. Just make sure whatever you go with the fan is not a mile away from the radiator and run a shroud if you can. Any issues after that are likely to be state of tune problems.
 
The average normal pressure of a Mopar cooling system is right around 16lbs. Have you flushed your system?? How about taking it to your local radiator shop and having them test the pressure?? Its as simple as removing the cap and installing a radiator pressure tester. They may not even charge you for the test!!


I suspect the 19" radiator myself as it was not intended for the V8 setup, although many people still use them anyway with no problems. I think the above mentioned changes to a 22" radiator with a shroud and a 7 blade fan will go a long way to helping your overheating problems. Geof
 
I used a 3 core form a Jeep Cherokee, fit like a glove. Wall to wall (er,subframe rail to rail) radiator and the ports were close to original, just had to use a fles hose for the top (ugly) but you could find a suitable adaptable one. Check your pump, as stated, the pumps can deteriorate over time, actually rusting off the shaft. All the threads covered 90% of the potential causes. check for a hot radiator cold spots, uncap COLD radiator and check for circulation or bubbles (blown head gasket) Get yourself a bottle of pool acid and do a block flush (careful, do it in the street as itll etch concrete, Google it so you know how to do it right) or finally hit the scrap yard and fins another 22 radiator. We ran a 18 '64 radiator with a 340 and it worked in a mild So. Cal Climate. Dont know about hot as Hades Texas...vacationed with relatives a few times in north east TX in july, I 'bout melted....
 
If you have an aluminum intake or other aluminum cooling system-interfacing parts, and are not using DISTILLED water in the radiator with your coolant, you could have electrolysis occurring which results in a buildup of hydrogen while it corrodes the holy hell out of your system.

It builds a LOT of pressure.
 
If it's leaking at the solder joints, check your electrical grounds!
 
Ok after many fixes (crap patches) I've discovered the radiator cap is actually being hit by the hood. I relocated the rad 1" lower, but am convinced this has to be replaced. Keeps springing leaks because of the flexing the old copper beast does.

Question now: 2 core or 3 core whats the difference overall?

And until I get the answer / shipped radiator what jeep cherokee year model (as i've read will do for the short term?)
 
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