93 Explorer Cooling Issues, WTF?
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Senior User
Joined: Dec 2002
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From: Port Angeles WA
93 Explorer Cooling Issues, WTF?
Ok Fokes here is the deal. 1993 Explorer 4x4 4.0L Auto trans with A/C. When I start the rig in the morning the temp guage will slowly creep up and get all the way up to HOT (Just below the Red) and then back off a little bit back down to high normal. After that the temp guage will bounce back and forth from Hot, to High normal and it will stay this way. I have replaced the thermostat, and the radiator, and the heater core and no change. It started doing this after I used some of that radiator sealant junk on my old radiator to stop a small leak but now with a brand new radiator its doing the same thing.
Also, I am no longer getting hot air from my new heater core either. About the only thing I have not replaced on this cooling system is the water pump but it seems to me that a water pump either works or doesn't right? The truck never does "Overheat" but it gets VERY close to it which I don't like and now that we are headed into the winter months, I need that heater core to work.
Any thoughts or ideas?
Thank you
Also, I am no longer getting hot air from my new heater core either. About the only thing I have not replaced on this cooling system is the water pump but it seems to me that a water pump either works or doesn't right? The truck never does "Overheat" but it gets VERY close to it which I don't like and now that we are headed into the winter months, I need that heater core to work.
Any thoughts or ideas?
Thank you
Postmaster
Joined: Oct 2003
Posts: 4,516
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From: SoCal
A friend of mine had the exact same problem on a 350 Chevy & it was a bad pump
The impeller had broken lose from the pump shaft.
Try this, warm it up, squeeze the upper hose & rev it up. Do you feel a surge of water?
The impeller had broken lose from the pump shaft.
Try this, warm it up, squeeze the upper hose & rev it up. Do you feel a surge of water?
Senior User
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Does sound like a flow issue. Either a bad pump, thermostat or that radiator gunk still in the system clogging it up somewhere. Look down the rad cap hole after it's all warmed up and see if the flow is consistent through the radiator. Try flushing the system and then a new pump if all else fails.
Thread Starter
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Senior User
Joined: Dec 2002
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From: Port Angeles WA
I will give that a try tonight. So you saying that the impeller may be slipping on the shaft which when the stat opens, its not pumping efficiently because of the extra resistance on the impeller?
Postmaster
Joined: Dec 2001
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From: UT
Have you checked the operation of the fan clutch? I've had similar overheating issues from a faulty fan clutch.
Your heater core might be clogged. I've found that I have to backflush my heater core every year or two.
Your heater core might be clogged. I've found that I have to backflush my heater core every year or two.
Postmaster
Joined: Dec 2001
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From: UT
Whose heater core did you get. My original Ford heater core didn't have problems with clogging up. The cheap Autozone replacement core that I put in clogs up all the time. I can't remember how quickly it clogged up the first time.
Not saying that it can't be the water pump impeller. This wouldn't be the first time I've heard of that happening on an Explorer.
Another thought: have you verified that gauge is correctly representing temperature? That dash gauge can just as effectively measure problems in the wiring as it can the temperature. When I've wanted to check the dash gauge, I've just put a voltmeter across the computer's ECT sensor and compare the ECT output against the dash gauge.
Not saying that it can't be the water pump impeller. This wouldn't be the first time I've heard of that happening on an Explorer.
Another thought: have you verified that gauge is correctly representing temperature? That dash gauge can just as effectively measure problems in the wiring as it can the temperature. When I've wanted to check the dash gauge, I've just put a voltmeter across the computer's ECT sensor and compare the ECT output against the dash gauge.
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Senior User
Joined: Dec 2002
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From: Port Angeles WA
I did use the Cheap-o Heater core for $20 and the thought of the gauge being the issue did cross my mind also but based on the behavior of the rig I think its accurate. When the temp reads very high (Almost to the Red) the motor kicks up the idle like it should and as soon as the stat opens the temp goes down to normal and the engine idles down also.
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Don't know if it relates, but Ford had a problem with temp gauge problems. Specifically, the block sensors gave false readings and the temp gauge would rise and fall. The block isn't overheating, in that case....it's just that the sensors aren't balance.
Bad news is, even if you find the parts to fix the problem, it still will cost over $200. If you have it done for you, it's over $300.
Hope it helps.
Bad news is, even if you find the parts to fix the problem, it still will cost over $200. If you have it done for you, it's over $300.
Hope it helps.
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