Cooling system issue - overpressurization?
#1
Cooling system issue - overpressurization?
Heya gents,
My 1999 4.6L is running well, but I'm using coolant / water to some degree, AND it's as if I have an over pressurized system.
I say over-pressurized because I blew an original heater hose once, but it happened AFTER I shut the truck off and walked away from it. At that time I knew that my filler-cap would occasionally whistle (letting out pressure), so I bought a new, and proper-pressure, filler cap for the truck shortly after replacing that hose.
But even with the new one I hear it off-gassing when I shut the truck off some days, and today I both heard it while driving AND the temperature gauge started rising at a stop light. (I thought that is was out of water, so I drove it some more to get to a parking lot, but the temp gauge went right back to normal and stayed there both at the next stop lights and in the parking lot, and when I finally could open the reservoir, it had plenty of water in it.)
So I'm left guessing at a few causes here.
Where is my water going to? Yeah, I don't want to think it is, but certainly a head gasket could be an issue - but I never see any steam out of the exhaust.
What is causing the over-pressurization? Well, that could be a head gasket, too, but could it be a stuck thermostat? I only ask based on what I saw the temp gauge do today.
I wish I could just find an external leak and know that that's where my water goes, but... ugh.
Still, if there is an over-pressurization, perhaps the water is being pushed out of an overflow tube since the cap is often letting pressure out (whistling)?
I really can't figure out why it would both whistle, and nearly overheat, if there was enough water in the system today.
My 1999 4.6L is running well, but I'm using coolant / water to some degree, AND it's as if I have an over pressurized system.
I say over-pressurized because I blew an original heater hose once, but it happened AFTER I shut the truck off and walked away from it. At that time I knew that my filler-cap would occasionally whistle (letting out pressure), so I bought a new, and proper-pressure, filler cap for the truck shortly after replacing that hose.
But even with the new one I hear it off-gassing when I shut the truck off some days, and today I both heard it while driving AND the temperature gauge started rising at a stop light. (I thought that is was out of water, so I drove it some more to get to a parking lot, but the temp gauge went right back to normal and stayed there both at the next stop lights and in the parking lot, and when I finally could open the reservoir, it had plenty of water in it.)
So I'm left guessing at a few causes here.
Where is my water going to? Yeah, I don't want to think it is, but certainly a head gasket could be an issue - but I never see any steam out of the exhaust.
What is causing the over-pressurization? Well, that could be a head gasket, too, but could it be a stuck thermostat? I only ask based on what I saw the temp gauge do today.
I wish I could just find an external leak and know that that's where my water goes, but... ugh.
Still, if there is an over-pressurization, perhaps the water is being pushed out of an overflow tube since the cap is often letting pressure out (whistling)?
I really can't figure out why it would both whistle, and nearly overheat, if there was enough water in the system today.
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ghanson
1999 to 2016 Super Duty
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08-13-2011 08:55 AM
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1987 - 1996 F150 & Larger F-Series Trucks
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