So we just changed out the driver's side header gasket on a 95 Z28. The only things we unplugged (intentionally anyway) were the brake booster vacuum line, and the #1 and #7 plug wires (for better access to the header bolts).

Everything is back together and the car is running great - no more tick-tick-tick-tick from the header. The only problem is the temp gauge is not registering anything. It won't move at all (the needle sits below the first markings). It was working just fine prior to doing the header gasket...

Any ideas what might have caused that? I'm thinking we probably unintentionally unplugged a connector somewhere, not sure where to look though.

 

There is a coolant sensor in the driver side head, just on the outside. It may be a bit obscured by the header and can be found between #1 and #3 exhaust ports. You have either knocked it loose or broken the sensor. This sensor is very easy to break off too.

Definitely one of those two things.

 

Here's a picture.

http://shbox.com/1/temp_sensor2.jpg

 

Thanks, I looked and sure enough it was unplugged. No idea how that happened!