I have a 1998 expedition that runs fine then out of the blue water temp needle jumps to all the way hot. After i shut off the truck and wait a minute i restart and temp is fine. this happenes every couple of trips. i changed the t-stat and it still does the same thing. I hear lots of water running sounds while accelerating, but not at idle. The water can not cool down that quick so im puzzled. also one of the times the needle pinned hot i shut off engine, popped hood and upper hose was hard as a rock. that doesnt sound right. does it? I ran at idle with cap off and no air was purged. So im stuck dead in the water.........
The rock hard hose is a sign of high pressure in the cooling system caused by a blown head gasket.
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It could just be a bad temp sensor giving a false reading to the gauge. The upper hose being hard isn't necessarily a death nell for the headgasket. It will be firm because the system operates under 12-15 lbs of pressure.
Is there coolant in the oil or oil in the coolant? Those would be indicators of a headgasket problem.
__________________ 1999 Expedition XLT, big and green, 5.4, 4x4, 285/70-17 Dunlop MT's, factory skid plates, magnaflow muffler.
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Overheating but not really ????!!!!!!
I have a 1998 expedition that runs fine then out of the blue water temp needle jumps to all the way hot. After i shut off the truck and wait a minute i restart and temp is fine. this happenes every couple of trips. i changed the t-stat and it still does the same thing. I hear lots of water running sounds while accelerating, but not at idle. The water can not cool down that quick so im puzzled. 
also one of the times the needle pinned hot i shut off engine, popped hood and upper hose was hard as a rock. that doesnt sound right. does it? I ran at idle with cap off and no air was purged. So im stuck dead in the water.........
1999 Expedition XLT, big and green, 5.4, 4x4, 285/70-17 Dunlop MT's, factory skid plates, magnaflow muffler.
