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Weird heating problem

Chris Reed's Avatar
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10-09-02, 02:01 PM   #1  
Chris Reed
Weird heating problem

I have a 1999 Ford Explorer with 66,000 miles. In the past two months, whenever I drive after the car has been sitting cold for a few hours, if I have to go up to 65 miles per hour or more, the thermostat steadily increases until it's past the high limit, and my gauge begins warning me of an overheating problem. Then I slow down a bit, and the gauge goes down never to be a problem again during my travel. This only happens within the first eight or so minutes I'm operating the car.

The fluids seem OK. I'm at a loss as to what's going on. And I don't trust the only mechanic readily convenient to me to do anything but recommend vast and costly repairs. But I'm worried that the persistence of the problem suggests something major is wrong.

Any theories on what's wrong and what I should do?

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davidf's Avatar
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10-09-02, 03:38 PM   #2  
weird thermostat

Most likely the thermostat is sticking closed until a lot of heat causes it to pop open instead of opening gradually.

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10-09-02, 03:50 PM   #3  
I agree.

Chris Reed's Avatar
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10-09-02, 04:38 PM   #4  
Chris Reed
But what should I do?

Appreciate the diagnosis -- but is there something I can do to fix this or do I need someone with tools, etc.?

Thanks for the help!

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10-09-02, 07:46 PM   #5  
You have to drain the coolant and remove a few parts. Here's some info on the repair. You dont mention what engine you have?

Explorer Repair Link

4.6L, 5.4L And 6.8L Engines

Disconnect the negative battery cable.
Drain and recycle the engine coolant.
Remove the power steering reservoir support bracket.
Remove the upper radiator hose at the thermostat housing.
Remove 2 thermostat housing retaining bolts and remove the housing.
Remove the thermostat and O-ring from the lower intake manifold. Discard the O-ring.
To install:
Clean the O-ring sealing surfaces.
Install a new O-ring, on the thermostat and position the thermostat in the lower intake manifold.
Place the thermostat housing on the lower intake manifold and install 2 retaining bolts. Tighten the bolts to 15-22 ft. lbs. (20-30 Nm).
Install the power steering reservoir support bracket.
Fill the engine cooling system.
Connect the negative battery cable.
Start the engine and allow it to reach normal operating temperature while checking for coolant leaks.
Road test the vehicle and check for proper engine operation.
Check the coolant level and add if necessary.

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10-10-02, 03:52 AM   #6  
If you don't have a basic set of metric wrenches, sockets and other hand tools, then yes, there's not much you can do .

If you can follow Stevo's directions and have the basic hand tools, then I believe you can do it

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