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Old 12-21-2012, 05:20 PM
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Engine is running too cold?

I have a 1973 Javalin with a 232 6 cylinder and manual 3 speed transmission. I had a stock radiator that kept splitting open and leaking so I decided to replace it with a similar size new aluminum radiator. Ever since I installed this radiator the engine does not reach operating temperature. Now that winter is here, the heater does not blow hot air. To remidy the problem I put a piece of cardboard in front of the radiator with a hole cut out in the center about 4.5 inches in diameter. To my surprise this did not help one bit. The gauge starts out reading below the cold mark then comes up to the cold mark as you drive the car. With the old radiator the needle would pass the cold mark by 3/8 inch which indicated normal operating temperature. The radiator is the only thing I changed out. Everything else remains the same in the car. The problem occured right after I installed the new radiator.

Any ideas on what to do?

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Old 12-21-2012, 05:26 PM
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Originally Posted by HotRodMan View Post
Any ideas on what to do?
I'd start by installing the stock temp thermostat.

Last edited by techinspector1; 12-21-2012 at 05:31 PM.
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Old 12-21-2012, 05:44 PM
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aluminum transfers heat pretty efficiently. i've heard other people say the same thing after they dropped aluminum radiators into their rides.
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Old 12-21-2012, 07:17 PM
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With good aluminum radiator it may be needed to use a electric fan setup. It is not hard to gwt working. I think painless and alotof other people make a wiring kit then it will heat up fans may never run in the winter but they will kit on in the summer when it gets hot.

Also check the therostat its probably leaking and letting water flow all the time so it does not have time to get hot. Electric fan kit may not help if its bad whenon the highway it will still cool the water with moving air.
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Old 12-21-2012, 09:55 PM
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check the fluid level,check upper and lower hoses with bare hands,make sure warm water is coming out of the engine.then you will know something??? thermostat might be open
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Old 12-21-2012, 10:47 PM
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I side with Tech and Vinnie and Hcompton Check the thermostat!!!!

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Old 12-22-2012, 05:09 AM
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I had problems with low heat in my Ford Expedition and assumed that it was not the thermostat because I had replaced it with a new OEM 195 degree thermostat when I serviced the cooling system. However, after several months of troubleshooting I finally replaced the thermostat again with another new one, which solved the problem.

Thermostats are a simple device, but I've learned to always test them before installation. Some open too early or too late, and others don't seem to react fast enough to keep a stable engine temp under varying load.

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Old 12-22-2012, 08:15 AM
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Do you have a clutch fan? I am betting not and it always runs full steam hot or cold. Adding a clutch fan may help a little once the other issues are sorted. I dont think the 6 can as a clutch fan. A flex fan can be a cheap fix but the proper clutch fan will help you save some hp and keep stock look.

If thermostat is rusted thru and the fan is large solid mount fan it will run cold as it can. Even with stock radiator. Did it run hot and cold with the stock radiator. Or was ot clagged up with junk. If so i would flush the system again since some trash has probalby clogged the thermostat and holding it open. On some old cars its worth the time to pull the thermostat and hook the top hose to a bucket and floor the car once to blow the crap out of the block. But maybe not the best solution sometimes needed if major rust problems.

Will it get hot if you open the hood and cover the entire front of the car with a shop blanket. It should heat up with a blanket no matter what. Also easiest way to check the thermostat operation for older cars without electric fans.
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