Re: 1941 Packard Clipper Eight Special Sedan

Posted by HH56 On 2017/10/14 10:43:30

Quote:
Only if it is stuck closed or otherwise defective. If it has a really high opening temp such as being an optional 190 degree thermostat used for special climates then the engine would get fairly warm before it opens but as soon as it does open the temp should stabilize around that area.

If it is the original bellows type thermostat and you are running a high pressure cap then those have a problem opening when the pressure gets over 7# or so but they eventually do open. If it is a modern capsule type thermostat those can fit in the housing either way. Make sure it is mounted so the sensing pellet is down and towards the head.

Have you used a mirror or some other means to visually look in the cap opening to see if coolant is circulating. If you see no action in the radiator tank then look to the thermostat or some other blockage. If the coolant is flowing then look to one of the other causes.