Thanks for the reply. It's indeed an '86...built in May, IIRC. Good idea on carquest...or maybe NAPA could find something. There is a thread here about a mystery sensor on the side of the head near the injector lines. The sensor I'm talking about is the same sensor...and I've determined that this sensor just threads into the head, but doesn't extend into the coolant stream. I did some testing on it and found that one prong is grounded and the other switches to trigger the warning alarm. To my surprise, it works...so I'll just re solder the connections. The strange part is that the sensor has the 2 prongs as I mentioned, but it has only one wire that extends from the plug which plugs into the wiring harness. Strange. I thought that I could T into the front sensor(near #1 injector) and run a modern coolant temp sensor that actually will give a more accurate reading of coolant temperature.