BKCowGod
Well-Known Member
Hi all -
Patient is my '65 Dart slant. I have verified using both an IR thermometer and a resistance box that my gauge is accurate enough to be trusted. Ambient temps have been between 60 and 95. The gauge usually rises to (or lowers to if it's been parked hot) the first line and then stays centered on that line, with the expected minor variations as the thermostat opens and closes.
But every once in a while it rises to the second line and then the variations become more pronounced, making it 2/3 of the way to the third line and then back down to 1/2 way between the 1st and the 2nd before settling again in the middle. I have not seen it hit the third line, but if it makes it to the second line it will not settle back at the first one.
My working theory is a partially stuck thermostat, but it just seems so danged precise about when and how it happens that I thought I would consult the brain trust. I am also aware that none of this is overheating, but I have learned to watch any deviation from the norm, and normally it is pretty rock steady at line 1, even in 100+ temps, idling with the AC blasting.
For visual reference, it is between what I am calling lines 1 and 2 in this pic.
Patient is my '65 Dart slant. I have verified using both an IR thermometer and a resistance box that my gauge is accurate enough to be trusted. Ambient temps have been between 60 and 95. The gauge usually rises to (or lowers to if it's been parked hot) the first line and then stays centered on that line, with the expected minor variations as the thermostat opens and closes.
But every once in a while it rises to the second line and then the variations become more pronounced, making it 2/3 of the way to the third line and then back down to 1/2 way between the 1st and the 2nd before settling again in the middle. I have not seen it hit the third line, but if it makes it to the second line it will not settle back at the first one.
My working theory is a partially stuck thermostat, but it just seems so danged precise about when and how it happens that I thought I would consult the brain trust. I am also aware that none of this is overheating, but I have learned to watch any deviation from the norm, and normally it is pretty rock steady at line 1, even in 100+ temps, idling with the AC blasting.
For visual reference, it is between what I am calling lines 1 and 2 in this pic.