coolant help
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coolant help
94 f250 351w 4x4
Just changed water pump and stat and sender, filled with 50/50, squeezed upper hose to get air out. Kept overflow full and drove for 2 days. It drank coolant from overflow at night and I refilled it, it did not drink it all. On first day gauge was at 1/2 on day 2 gauge at 7/8 so I stopped and looked, all seems fine, overflow is 3/4 full. Restarted and gauge goes to 1/2 and stays there. I turn it off and wait 10-15 min and turn key on and gauge is at 7/8 I start it and gauge goes to 1/2. Is this normal? Stat stuck? Also upper hose when hot, there is so much pressure you cannot squeeze it, when cold it feels like there is no coolant in it Is this normal?
Just changed water pump and stat and sender, filled with 50/50, squeezed upper hose to get air out. Kept overflow full and drove for 2 days. It drank coolant from overflow at night and I refilled it, it did not drink it all. On first day gauge was at 1/2 on day 2 gauge at 7/8 so I stopped and looked, all seems fine, overflow is 3/4 full. Restarted and gauge goes to 1/2 and stays there. I turn it off and wait 10-15 min and turn key on and gauge is at 7/8 I start it and gauge goes to 1/2. Is this normal? Stat stuck? Also upper hose when hot, there is so much pressure you cannot squeeze it, when cold it feels like there is no coolant in it Is this normal?
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Joined: Nov 2007
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From: Denver Metro Area, CO
Sounds like it could be normal to me, too... ever since Ford changed how the senders & gauges operate (87 or 88ish) that gauge tends to suddenly read real high as soon as you shut the ignition off... possibly the gas gauge does the same thing, I don't remember.
But if I'm understanding you correctly, you don't have anything to worry about....
But if I'm understanding you correctly, you don't have anything to worry about....
Moderator
Joined: Nov 2007
Posts: 22,415
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From: Denver Metro Area, CO
OK... Please clarify, then...
The first thing I would do is verify the electrical connection at the temperature sending unit... if you remove that connector and turn the ignition switch on, the gauge should read full LOW... leave the switch on, now ground that wire; the gauge should read full HOT (don't leave the wire rounded like that for real long). That sending unit varies the resistance to ground, this is how it makes the dash needle swing back and forth.
But if you ask me, the gauge shouldn't be getting that far to the HOT side in normal operation... possibly the gauge us lying, possibly it really *is* getting that warm... which a hand-held laser thermometer can help you diagnose.
Just changed water pump and stat and sender, filled with 50/50, squeezed upper hose to get air out. Kept overflow full and drove for 2 days. It drank coolant from overflow at night and I refilled it, it did not drink it all. On first day is this before or after the two days you drove it described above? gauge was at 1/2 on day 2 gauge at 7/8 at what point of the driving cycle was this? IOW was it like that with the engine off? Or after having been running and had warmed up? so I stopped and looked, all seems fine, do you have a hand-held laser thermometer? overflow is 3/4 full. Restarted and gauge goes to 1/2 and stays there. after how much time after restarting the engine? I turn it off and wait 10-15 min and turn key on and gauge is at 7/8 I start it and gauge goes to 1/2. THIS is normal - the coolant absorbs heat but isn't circulating, the gauge will reflect that... but the gauge reads too high if you ask me Is this normal? Stat stuck? Also upper hose when hot, there is so much pressure you cannot squeeze it, that's normal when cold it feels like there is no coolant in it Is this normal?
But if you ask me, the gauge shouldn't be getting that far to the HOT side in normal operation... possibly the gauge us lying, possibly it really *is* getting that warm... which a hand-held laser thermometer can help you diagnose.
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Joined: Nov 2007
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From: Denver Metro Area, CO
Another thing you could try kinda quickly is to put your old sending unit back in place and see if the gauge's behavior returns to something more normal (why did you change that thing, anyway?). I hope you didn't try to seal the threads with RTV or something like that, that device needs an electrical connection to ground through those threads and interfering with that can very easily cause the weird behavior you're seeing....
You can also put the thermostat in a small pot of water on the stove and watch it open up as the water heats up (which will happen kinda slowly, but it should be fully open at the time of its rated temperature).
You can also put the thermostat in a small pot of water on the stove and watch it open up as the water heats up (which will happen kinda slowly, but it should be fully open at the time of its rated temperature).
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From: Northern Indiana USA
One thing to remember, when you drive the truck, and shut it down, temp may climb slightly, because the coolant isn't moving. It should go down almost immediately.
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Posting Guru
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Another thing you could try kinda quickly is to put your old sending unit back in place and see if the gauge's behavior returns to something more normal (why did you change that thing, anyway?). I hope you didn't try to seal the threads with RTV or something like that, that device needs an electrical connection to ground through those threads and interfering with that can very easily cause the weird behavior you're seeing....
You can also put the thermostat in a small pot of water on the stove and watch it open up as the water heats up (which will happen kinda slowly, but it should be fully open at the time of its rated temperature).
You can also put the thermostat in a small pot of water on the stove and watch it open up as the water heats up (which will happen kinda slowly, but it should be fully open at the time of its rated temperature).
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94 f250 351w 4x4
Just changed water pump and stat and sender, filled with 50/50, squeezed upper hose to get air out. Kept overflow full and drove for 2 days. It drank coolant from overflow at night and I refilled it, it did not drink it all. On first day gauge was at 1/2 on day 2 gauge at 7/8 so I stopped and looked, all seems fine, overflow is 3/4 full. Restarted and gauge goes to 1/2 and stays there. I turn it off and wait 10-15 min and turn key on and gauge is at 7/8 I start it and gauge goes to 1/2. Is this normal? Stat stuck? Also upper hose when hot, there is so much pressure you cannot squeeze it, when cold it feels like there is no coolant in it Is this normal?
Just changed water pump and stat and sender, filled with 50/50, squeezed upper hose to get air out. Kept overflow full and drove for 2 days. It drank coolant from overflow at night and I refilled it, it did not drink it all. On first day gauge was at 1/2 on day 2 gauge at 7/8 so I stopped and looked, all seems fine, overflow is 3/4 full. Restarted and gauge goes to 1/2 and stays there. I turn it off and wait 10-15 min and turn key on and gauge is at 7/8 I start it and gauge goes to 1/2. Is this normal? Stat stuck? Also upper hose when hot, there is so much pressure you cannot squeeze it, when cold it feels like there is no coolant in it Is this normal?
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