FlatIron
New Member
- Joined
- January 17, 2009
- Messages
- 6
- Reaction score
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- City, State
- Music City, Tennessee
- Year, Model & Trim Level
- '96 XLT tow pkg
Great forum-
I've seen a few threads on this but I think I have covered the obvious stuff already. '96 XLT 4.0 4WD w/ about 146K, had it since new. Wife noticed engine running hot, not quite in the red but 'check gage' was lit. Limped home and I replaced the thermostat with a new Stant 195 degree unit. New thermostat did not have a 'equalizing' hole. Added coolant, refilled resevoir, re-added coolant until full while running w/ heat on high, closed cap and went for a test drive.
Engine temp was cycling from hot 'check gage' to cool. Temp of heater air would drop to cool whenever the gage was climbing, then would become hot again, heater air temp would cool down. Temp would always cycle back down after hitting hot, and as the gage moved down the heater air would heat up again. Drove up and down hills around the house for half hour, hot/cool cycling seems independant of acceleration. Didn't matter if I was going up a hill or down, or on the flats- seems to have a mind of its own. I thought it was beginning to self regulate and stop cycling, but before returning home did it again. It's about 32 degrees outside which is cold but not as bad as our record lows around 4 degrees last week. Oil looks OK, exhaust OK, and I don't see any leaks while the engine is running. Replaced the coil pack today also for another issue, temp problem no better or worse after replacing the coil. Dipstick and oil was warm but not hot, overall the engine did not seem hot. Refilled radiator again.
Could the problem be trapped air in the coolant system? Even after the radiator refills? Bad luck with the new thermostat? Would drilling a 1/8" hole in the thermostat do any good? Any help advice most appreciated. Oh for the simplicity of my '32 pickup... :roll:
I've seen a few threads on this but I think I have covered the obvious stuff already. '96 XLT 4.0 4WD w/ about 146K, had it since new. Wife noticed engine running hot, not quite in the red but 'check gage' was lit. Limped home and I replaced the thermostat with a new Stant 195 degree unit. New thermostat did not have a 'equalizing' hole. Added coolant, refilled resevoir, re-added coolant until full while running w/ heat on high, closed cap and went for a test drive.
Engine temp was cycling from hot 'check gage' to cool. Temp of heater air would drop to cool whenever the gage was climbing, then would become hot again, heater air temp would cool down. Temp would always cycle back down after hitting hot, and as the gage moved down the heater air would heat up again. Drove up and down hills around the house for half hour, hot/cool cycling seems independant of acceleration. Didn't matter if I was going up a hill or down, or on the flats- seems to have a mind of its own. I thought it was beginning to self regulate and stop cycling, but before returning home did it again. It's about 32 degrees outside which is cold but not as bad as our record lows around 4 degrees last week. Oil looks OK, exhaust OK, and I don't see any leaks while the engine is running. Replaced the coil pack today also for another issue, temp problem no better or worse after replacing the coil. Dipstick and oil was warm but not hot, overall the engine did not seem hot. Refilled radiator again.
Could the problem be trapped air in the coolant system? Even after the radiator refills? Bad luck with the new thermostat? Would drilling a 1/8" hole in the thermostat do any good? Any help advice most appreciated. Oh for the simplicity of my '32 pickup... :roll: