My ride is a 1992 Full size Blazer - just had some work done (power steering leak and manifold water leak) now the wter temperature gauge seems to be connected to the RPM of the engine. the gauge fluctuates from 150 to 260 and it seems to be with the RPM of the engine. The shop replaced the sensors but has no other answers. Help?

 

shot in the dark here, but is it possible that when they were working on it they somehow got the wiring for the temp gauge too close to the coil wiring or something?(I have no idea if this could even happen)
In any case I would go over everything they touched, if it wasn't that way when you dropped it off to them than it could have been caused by them.

 

I will take a look and let you know. Could an air bubble at the sensor cause this problem

 

possible it got a air bubble in it. but with these old v8s i never really had any problem with that. you usually just fill it up, run it til the thermostat opens it and refill it back up and done, air gone.

check your antifreeze lever and watch to make sure your thermostat opens. like make sure both hoses upper and lower are hot when the temp gauge reaches 190

edit... after re reading your post if its actually reving up with the engine, thats just strange.