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  #1  
Old 05-16-2011, 12:07 PM
FX4OR FX4OR is offline
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Default thermostat failure

hey guys just a quick question.

can a thermostat fail in the way that it will open too soon?
my engine never gets to the middle of the temp gauge, sits right under the middle point. i know its closed at first, because the upper hose has no pressure, but when I park after a drive, the upper hose is pressurized, so it is opening and closing. I just always thought they failed open or closed, no in between.

I had it flushed recently to see if that would help it, but didn't
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Old 05-16-2011, 04:15 PM
TomN TomN is offline
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Default Re: thermostat failure

Im not sure, but I know mine failed open. It is an easy part to change (on the OHV, prolly the same on the SOHC). It's cheap to, so it really doesn't hurt to just change it.
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Old 05-16-2011, 04:21 PM
djfllmn djfllmn is offline
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Default Re: thermostat failure

Quote:
Originally Posted by FX4OR View Post
hey guys just a quick question.

can a thermostat fail in the way that it will open too soon?
my engine never gets to the middle of the temp gauge, sits right under the middle point. i know its closed at first, because the upper hose has no pressure, but when I park after a drive, the upper hose is pressurized, so it is opening and closing. I just always thought they failed open or closed, no in between.

I had it flushed recently to see if that would help it, but didn't
where your temp guage is normal...fords almost never get into the middle of the normal range...my 95 barely got into the normal range and it threw heat no problem...and my trucks guage sits just under the middle point when its warmed up unless its really hot out...where your gauge sits is no need for concern
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Old 05-16-2011, 04:33 PM
TomN TomN is offline
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Default Re: thermostat failure

i missed that part. haha. Ya, your fine. Mine sits just below the middle too.
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  #5  
Old 05-16-2011, 06:09 PM
Botta Ranger Botta Ranger is offline
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Default Re: thermostat failure

From a cold start, hold your hand on the upper hose. It should stay cool for a few minutes then warm up all of a sudden when the thermostat opens.

Not understanding your pressure diagnosis.
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Old 05-16-2011, 06:17 PM
01B3000 01B3000 is offline
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Default Re: thermostat failure

Well, fail as in stayed open it will be overcooling, fail as in stay closed, with a bad radiator cap like mine, your gonna blow a seal in your water pump, like i did.
I changed mine to a 185* thermostat, but before i did it always sat just blow half
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Old 05-16-2011, 08:05 PM
FX4OR FX4OR is offline
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Default Re: thermostat failure

thanks for the replies,
the reason i think something is wrong is because the upper radiator hose is never *HOT* i.e., i can grab it after a 20 mile highway drive and it is by no means too hot to touch, only somewhat warm.
the truck also struggles to hold heat when I'm not going uphill, and the heater never really gets HOT either- again, only warm. the temp gauge plummets when I go downhill, making the heater go cold. the coldest ambient temp it sees during this course of events is probably 50 degrees.
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Originally Posted by Botta Ranger View Post
Not understanding your pressure diagnosis.
cold engine - no pressure in the upper hose (thermostat closed)
"warm" engine - pressure in upper hose (thermostat open)
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  #8  
Old 06-12-2011, 05:52 PM
FX4OR FX4OR is offline
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Default Re: thermostat failure

yeah, Im bumping this...

1 new thermostat later, and the needle parks itself exactly at the middle, and my heat is blazing hot. problem solved lol, in case anyone comes across this thread in the future. (this is assuming they actually use the search button lol)
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