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1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks Discuss the Early Eighties Bullnose Ford Truck

Overheating

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Old Oct 3, 2015 | 09:27 AM
  #1  
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Overheating

I have a 1986 F150 Lariat with an inline 6. When i drive the vehicle it heats up really quickly. If i turn on the vent or the heater I am able to maintain the temperature so that it does not over heat. Once the vehicle is turned off it takes a long time to cool. My question is is this is Thermostat / Water pump issue? I have looked into both and am honestly looking to just replace both of them. However, I cant find a blown up diagram in my Chilton's or any other literature that has the thermostat in it. Am I just missing it or am I completely off base. Any diagnosis suggestions or ideas on where to look are appreciated.

Thank you
 
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Old Oct 3, 2015 | 10:31 AM
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The heater core is a loop entirely before the thermostat.
If using it makes a diffrence then it points to the thermostat (or radiator)
 
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Old Oct 3, 2015 | 12:18 PM
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If the upper radiator hose does not become very hot to the touch and feel pressurized when the engine has warmed up fully, this suggests the thermostat may be stuck closed. That is an easy fix.

Or alternatively: coolant level may be very low, or pump went bad, or clogged radiator.
 
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Old Oct 3, 2015 | 12:23 PM
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Hey
It's like a 30 min job taking your time...
Just remember which way it goes.
Factory temp is 195.
 
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Old Oct 3, 2015 | 02:57 PM
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The radiator hose becomes very hot when in use. The coolant has also been changed and filled.
 
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Old Oct 3, 2015 | 04:08 PM
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Is the bottom hose cool enough to hold?
If not its likely your radiator is full of scale or sludge.

Change the thermostat for a genuine Motorcraft 192*.
Its cheap and just part of cooling system maintenence.

Stant and others are all seeing "cost cutting" measures.
FORGET about snakeoil feature thermostats. They're crap.
 
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Old Oct 3, 2015 | 04:21 PM
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First thing, how do you know it's overheating? A lot of money has been wasted on a faulty factory temp sending unit. Are you going by the gauge?
 
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Old Oct 3, 2015 | 06:45 PM
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The gauge as well as temp taken straight from the engine compartment. It could honestly be scale and sludge. It is an 86 with 103000 miles on it. I bought it this spring.
 
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Old Oct 3, 2015 | 11:35 PM
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Put a real set of gauges in it. Don't rely on the factory gauges for something like this.

The only good thermostat I've ever used is a Motorcraft RT1139, OEM 192* F thermostat. Had bad luck with the aftermarket brands.
 
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Old Oct 4, 2015 | 06:38 AM
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Originally Posted by Shonk86Lariat
The gauge as well as temp taken straight from the engine compartment. It could honestly be scale and sludge. It is an 86 with 103000 miles on it. I bought it this spring.
What readings did you get under the hood?
 
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