Good day all,
Yesterday while driving to work the temp gauge progressively went from its usual midway point to just below red in a matter of less than 5 minutes. No dash lights came on and as soon as I turned on the heater/defroster, the temp came down a couple of ticks. On my way home, I ran the defroster full blast from the beginning of my drive for about 15 minutes and the temp gauge stayed in its normal midway point. As soon as I turned off the defroster, the temp gauge climbed to the red in less than 1 minute. The car is now parked until I figure this out. Any thoughts immediately come to mind? The presumed overheating was taking place on a 55 degree day at highway speeds. I'm wondering if this is merely a sensor problem or something greater. I already have a new Walher 87 degree thermostat in hand and am probably going to replace the ECT sensor while I'm at it, but if anyone thinks this is definitely something else I would be most grateful for the input.
Thanks!

 

I could really, really use some input on this issue...even if its just reassuring me that the thermostat and/or ECT sensor are most likely the issue. If that is so, is there a way to get the thermostat off without taking the fuel system apart?
Thanks

 

Remove the thermostat and test with thermometer & pan of water boiling on stove. Use a meat thermometer.

 

Thank you for the heads up...before doing so, do you know of a way to get at the thermostat without taking apart the fuel system which blocks access to the rear T40 bolt?