86 F-250 6.9 over heating?
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86 F-250 6.9 over heating?
i just bought this truck as a fix er uper project to give me somthing to do on the weekends, well ive done more than that just trying to figure out why its over heating, the heads are good and same for the gaskets, all i can really think of is the thermostat or its just got to much power..haha if anyone who reads this knows please throw me some ideas, thanks
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Joined: Oct 2009
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From: Pontotoc, MS
Mine was leaking at the heater hose....maybe heatercore as well....
I know that the head gasket is notorious on these trucks but yours is good.
I would check the heater hoses and then lean toward the thermostat.
I'm gonna have to deal with that myself when I redo the return lines...not looking forward to it though....
I know that the head gasket is notorious on these trucks but yours is good.
I would check the heater hoses and then lean toward the thermostat.
I'm gonna have to deal with that myself when I redo the return lines...not looking forward to it though....
Lead Driver
Joined: Nov 2003
Posts: 6,900
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From: Campbell River, B.C.
Is the bottom of the rad getting hot? Did you install the last thermostat or was that done by the PO?
You must use only the OEM type and you can only get them from a ford or international dealer.
You must use only the OEM type and you can only get them from a ford or international dealer.
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Joined: Oct 2009
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From: Pontotoc, MS
Ok, I have an uncle who has worked on the 6.9/7.3 IDI trucks for 25 years or so, He says it doesn't matter what brand thermostat you use as long as it is made for the engine.
What is the problem that occurs without using the motorcraft or naistar?
Is it just that most Autozone/Advanced Auto stores sell junk?
What is the problem that occurs without using the motorcraft or naistar?
Is it just that most Autozone/Advanced Auto stores sell junk?
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From: Bald Knob AR
The cheap ones from the zone or other places don't have the built in bypass valve if I remember right.
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Posting Guru
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From: Perry Georgia
The aftermarket thermostats bought from Autozone, O'Reilly, advance and the rest of those places have the thermostat that has the little relief flapper, for lack of a better term built into the thermostat. You don't want one of those because the 6.9 has a built in bypass. I went thru thermostats from Advance, Oreilly and NAPA before I went back and bought one from Ford. Haven't had any trouble since than. Also are you going by the factory or an aftermarket temprature gage? The factory gages is one step from worthless.
Post Fiend
Joined: Feb 2009
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From: Ottawa, Ontario
Ok, I have an uncle who has worked on the 6.9/7.3 IDI trucks for 25 years or so, He says it doesn't matter what brand thermostat you use as long as it is made for the engine.
What is the problem that occurs without using the motorcraft or naistar?
Is it just that most Autozone/Advanced Auto stores sell junk?
What is the problem that occurs without using the motorcraft or naistar?
Is it just that most Autozone/Advanced Auto stores sell junk?
Heres why you cannot use anything else but a Motorcraft or IH thermostat in these engines, plus, a few members here have had first hand experience with that, they'll chime in sooner or later to break it to you as well.
https://www.ford-trucks.com/forums/1...l#post11218904
There is one aftermarket brand thermostat witch WILL work in these engines, and that's the Stant thermostat. It is made EXACTLY like the factory ones though, that's why it works.
Posting Guru
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From: Perry Georgia
I agree with IDIDIESELJOHN I used 2 thromostats from Advance and both of them went south within a few weeks. Personally If somebody wants to use other t'stats, that's their business. Myself, I know what works and will buy like is suggested. Thermostats AND glo plugs just to name a couple.
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