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1961 - 1966 F-100 & Larger F-Series Trucks Discuss the Slick Sixties Ford Truck

Backwards Heat issue

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Old Feb 27, 2011 | 10:53 PM
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Backwards Heat issue

I have an interesting problem that just doesn't make a lot of sense to me. I put a new radiator in my truck, 66 F100, 240 6 cylinder. When I bought the truck it had what appeared to be a stock radiator including a hole that squirted water out in a stream about the size of your index finger. This radiator has a filler panel to cover about 6-8 inches of the stock radiator hole. I checked on getting it rebuilt, but most of the prices I found were pretty high. So I found a radiator at Advanced Auto that claimed it would fit. So I bought it. It was about 4 inches wider than the original one. I was able to modify the filler bracket, and it all seems to work right, but the truck never gets to good operating temperature. I have driven my truck all day on a 50 degree day and it gets up to about 170 degrees. When I replaced the radiator I put a 180 degree thermostat in it. It was the lowest temperature thermostat I could get.

I understand that this radiator could keep the truck cooler, but I just have never seen a truck not heat up. Any ideas or suggestions would be appreciated.
 
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Old Feb 27, 2011 | 11:46 PM
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That's a good problem to have. I used to use a piece of cardboard to partially cover my radiator so the truck would warm up to operating temp and the heater would work. In the summer I didn't need the cardboard there, just in the winter. You could try a 195 thermostat to see if that helps but I typically don't like them that high. Jeff
 
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Old Feb 28, 2011 | 05:18 AM
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Bum, I suspect you may be suffering a little detailitus. Unless you have it calibrated it might not stand as tall as it once did. We live in a different world than when those old trucks were designed. That old gauge may only get close.

As long as you leave it down a couple inches in the neck for expansion, don't sweat it.




John
 
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Old Feb 28, 2011 | 07:27 AM
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Thanks for the info guys,

I was hoping for something nicer than cardboard in the grill. I may have to design something like the truckers use for the radiator support. Kinda like a bra.

Jo, I know I have a tendency toward details. The last slick I owned I could watch the gauge go up to the thermostat point and then drop slightly. I really don't think this truck is getting near the thermostat open point. I have even thought of pulling the fan off and putting an electric on so it would not have any cooling effect until it reaches operating temp.

Frankly the biggest issue I have with this is that without the truck reaching operating temperature, I barely have heat in the cab. In the summer this may be great, but it makes for cold days in winter and spring in Colorado.
 
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Old Feb 28, 2011 | 09:36 AM
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That's easy... replace the 180 thermostat with the stock 195. Now that the radiator is cooling the way it should be... the 195 thermostat will control the temperature in the way that it should.
 
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Old Feb 28, 2011 | 10:02 AM
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Originally Posted by Broomfieldbum
Thanks for the info guys,

I was hoping for something nicer than cardboard in the grill. I may have to design something like the truckers use for the radiator support. Kinda like a bra.

Jo, I know I have a tendency toward details. The last slick I owned I could watch the gauge go up to the thermostat point and then drop slightly. I really don't think this truck is getting near the thermostat open point. I have even thought of pulling the fan off and putting an electric on so it would not have any cooling effect until it reaches operating temp.

Frankly the biggest issue I have with this is that without the truck reaching operating temperature, I barely have heat in the cab. In the summer this may be great, but it makes for cold days in winter and spring in Colorado.
I hear ya on the cardboard thing, I used a piece I cut from a Ford parts box so it had a cool Ford oval on it. I would try the thermostat route first though as mentioned above. I don't drive my trucks in the winter (couldn't if I wanted to) so I don't run the higher thermostats.
 
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Old Feb 28, 2011 | 11:40 AM
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Bum, Have you considered flushing the heater core? Your truck may be like mine and have a lot of air exchange inside the cab, but if the heater core is getting a good flow of warm water in it, you should have heat in the cab.

Mine is leaking because I can smell it and the other day it was fogging the windshield.

But HEY, it's 80º here today, who needs it???? right?




John
 
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Old Feb 28, 2011 | 07:38 PM
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Thanks for all the info guys, but one thing just doesn't make sense to me. If I have a 180 degree thermostat that is never opening because the truck never gets to 180 degrees, how does putting a 195 help?

IE If it can't make it to 180 how would it ever make it to 195??

Jo, I did flush out the whole cooling system when I replaced the radiator. I would really like to get a deluxe heater for my truck, and then I would just get a new core for it when I do that install.
 
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Old Mar 1, 2011 | 04:49 AM
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Your post points back to the thermostat and or it's installation.




John
 
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Old Mar 1, 2011 | 08:53 AM
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I also have this problem in my 66 250, 300 6cyl. i cant get heat to the cab.in the dead of winter it'll keep a person from freezing to death but thats about all. I have to agree with John, maybe your thermostat is stuck open or maybe in upside down. i repalced the heater core and cleaned and fixed all the holes from airleak and it didn't help a thing so now i dont know what to do.
 
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Old Mar 1, 2011 | 10:32 AM
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6 Cyl radiators are smaller in width and use the filler panel stock. You purchased a universal fit radiator with the correct ford outlets.

Use some cardboard on the radiator if it runs to cold.

Did you rebuild the heater box? if not take it out and apart and clean the leaves and crap out of it. May just fint the nest of mice in there too as it is a direct shot to the cowl from the heater and a common area to find rodents.

Garbz
 
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Old Mar 1, 2011 | 10:54 AM
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How would it ever make it to 195?... by reducing water flow through the radiator! Where and how are you measuring 170 degrees? The engine temperature gauge is not necessarily accurate. The best way is to use a laser thermometer right at the thermostat housing.

Also, you should be getting at least some heat at 180. I would flush the heater core separately. I know from experience that flushing the system via the radiator won't get the heater core flushed if it's stopped up. Do this by removing the two 5/8" hoses from the engine and using a garden hose to force water through one of the hoses while watching junk fly out the other.

Is there a heater control valve installed? It could be rusted shut.

If you put in the correct thermostat and get water flowing through the heater core, you will get heat to the cabin.
 
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Old Mar 1, 2011 | 03:26 PM
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Originally Posted by jmf66
Where and how are you measuring 170 degrees? The engine temperature gauge is not necessarily accurate. The best way is to use a laser thermometer right at the thermostat housing.
X2. I will almost guarantee that your thermostat has opened and you need to look elsewhere for the heater problem.
On some engines, the temperature sender is positioned so that even if the gauge reads accurately, it will be 15-20 degrees cooler than the temperature at the thermostat.
 
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Old Mar 2, 2011 | 08:44 AM
  #14  
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when folks say "the cooler the better" with regard to vehicle operating temps....that is not necessarily true.

Optimum performance and fuel mileage is typically achieved at warmer operating temperatures.

The specific temperature varies for different types of engines, but you want a relatively high temperature that can be maintained and controlled.
 
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Old Mar 2, 2011 | 11:05 AM
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I had a very similar issue using a 4 core radiator in place of a 3 core on a 390. The t stat was a brand new 180 deg. It didnt matter how long the truck was ran the bottom hose would never get hot. We had plenty of heat inside the cab and the top hose was toasty including half of the radiator. As a last resort we tried a piece of cardboard and everything heats evenly now. I'm not sure how it will be in the summer but when its cooler like it is I guess that radiatior is just a little too big.
 
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