Originally Posted by 71MercKid
Okay. So here's the deal. Apparently our 78 T-bird is leaking antifreeze from somewhere. We replaced the upper rad hose and thermostat in hopes that this would solve the problem. Well. Upon reinstalling the Water outlet, it broke into two. We bought a new one. My father tried removing a sensor of some sorts from it and it broke. Any idea what it is? Its the little blue thing thats sticking out of the water outlet.
If it was a single wire sensor then it was Coolant Temp. Sender for the gauge or warning light on the dash. If it had vacuum lines to it then it was a Thermal Vacuum Switch for the Air Cleaner or one of the Emissions Control Systems. AllData doesn't have a picture of a 351M or 400C thermostat setup so I can't say with much certainty. If you can find the factory Service Manuals get them. Allot of the Ford ones in the 70's covered several vehicle lines so there wouldn't be a T-Bird Specific one, but find the 78 set and as long as it says it covers the T-Bird, you should be set.
Haynes has a manual covering several models, including the 75-82 T-Bird, though it isn't specific to your T-Bird. Most of the powertrain stuff will be the same between lines.
Chiltons doesn't appear to have a 77-79 Bird book, they still do have general repair books for powertrain, chassis, and limited electrical diagnosis, it's usually a thick green book. Check your local book stores, they may still sell them.