1999 Ford F150 engine runs cool

1999 FORD F-150
90,000 MILES • 6 CYL • 2WD • MANUAL
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JERRYGOODWRENCH
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customer brought this car in for no heat problem . We changed the thermostat,checked the heater core,flushed the cooling system,checked the clutch fan,.After all that the engine temp would not get above 130 degrees,So we covered the radiator temporialy with cardboard and still the temp will not go above 150 degrees(used laser temp gauge). The customer tells us that the radiator was changed in california. Would this be a contributing factor. Please help.
Nov 28, 2009 at 5:35 AM
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RASMATAZ
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If there's a problem with the radiator your readings will be higher, pull the Stat back out and run it w/o the stat and compare readings-You sure you got the right Stat
Nov 28, 2009 at 5:50 AM
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JERRYGOODWRENCH
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we took out the stat and engine runs even colder as it should, Put in a new 195 deg stant thermostat and same result temp won,t get over 140 or 150 deg even when rad is covered with card board. California radiator or too big. ????? I don't get it..
Dec 10, 2009 at 5:40 AM
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RASMATAZ
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The readings is it based on the temperature gauge or an infrared thermometer??

Low heater output/ruuning cool can also be caused by a thermostat stuck in the open position or the wrong temperature range thermostat. If the coolant temperature at the thermostat housing or radiator inlet is unusually low (140 degrees or less), the thermostat needs to be replaced.
Dec 10, 2009 at 11:03 AM
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JERRYGOODWRENCH
  • ✓ASE Certified Mechanic
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infared gauge pointed directly at thermostat housing . .Has new 195 deg thermostat (stant). Radiator is covered withh card board..
Dec 11, 2009 at 5:19 AM
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RASMATAZ
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The primary purpose of the thermostat is to control the engine temperature-Try using an OEM part and see what happens
Dec 11, 2009 at 5:35 AM
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