Classic Thunderbird Club International
Gil's Garage
Gil Baumgartner
CTCI Authenticity Chairman
1957 Thermostat

Because of its large opening the NAPA # 6 has been a very popular thermostat for our Thunderbirds.

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An alert tech article reader, Ted Woods, Palm City, FL, has brought to my attention a potential problem with this particular thermostat when used in 1957 models.

This thermostat functions fine with the 1955/56 intake manifolds, as well as the 1957 E models. The problem occurs on the 1957 intake manifolds because the heater control valve threaded port was moved forward to accommodate the larger carburetor.

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As the thermostat opens, it extends and contacts the extension pick up tube for the vacuum operated heater control valve P/N 18495 .  This problem can be eliminated by removing the extension tube on the bottom of the heater control valve.

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The extension is threaded into the valve and can be removed by turning it counter clockwise. Once removed the NAPA # 6 thermostat can open fully. Removal of the extension does not effect the operation of the heater control valve.

Gil Baumgartner

Last modified: September 11 2014