[240] Another temp gauge weirdness...

Probably the wrong sender, there are several different ones, and often two different ones on the same engine. One for the gauge and a different one for the engine computer. Dunno what the resistance should be off hand though.

That was my first thought. Double checking iPd, they only listed one. That's the one I bought. Maybe they got it wrong...

460191 Engine Temperature Sender Engine Temperature Sender Part#: 460191 Fitment: This is the sending unit for the engine temperature gauge in the instrument cluster

I bet I have an old mechanical gauge/sender laying around from my racing days. Maybe it'll fit and I can get a true reading.

Forgot to mention, also replaced the fan clutch. The old one freewheeled when I turned off the motor... not pushing much air that way. *g*

Well they're supposed to freewheel when the radiator temperature drops, but usually they have enough friction that they won't spin much.

You might have a bad gauge, or the wiring to the sender. There's a voltage regulator on the instrument cluster but it also controls the fuel gauge.

Usually a couple times around after turning off the motor.

I had driven 30 miles so it was warm. Just happened to lift the hood to check something while it was still running. Reached in and clicked it off. Fan was still spinning when I got back around to the front of the car...

After I replaced the thermostat, the motor warmed quicker. The gauge marches up to it's too warm spot consistently. That would imply the gauge is gauging something. The manual says grounding the sender wire and observe the gauge reads hot is the test for it. (why haven't I tried that yet?) Also says don't leave it grounded too long. When the sender broke the wire might have got up against the block or manifold. It was hanging out in space when I spotted the broken sender so I don't think so.

There's a

That's not the temperature compensator board is it? Thought I read somewhere those didn't come along until 1985.

Interesting idea though. I always check the gauges when I start the car... make sure they get off their stops. Recently, I've caught the fuel gauge climbing it's way up from empty as I'm a couple turns into my trip home from work. It wasn't that low when I drove off. Only happened once or twice, that I noticed.

No it's a separate thing. On the later cars (early 80s?) it's a small 3 terminal device that looks somewhat like a power transistor, while the earlier cars have a metal box about an inch long by half an inch square that plugs in with two terminals on the back of the cluster. I've never actually measured to see what the voltage ought to be.