Back when I was hunting down an F23 to swap I remember seeing temp senders on 98s & 99s and plugs on 00s & up. Since temp was already being measured by the ECT, I'm guessing Honda saved a couple $$ by eliminating the sender and driving the temp gauge with a a bit of added circuitry in the ECU. I don't have a diagram so I don't know for sure.

 

I had the Helm book for 98-99 and there was a sender for the dashboard gauge. I think(?) starting in 2000 the PCM worked the temperature gauge based on the ECT sensor.

 

Ok, So I got a new unit. The plug came out fine, but now I have turned the "top" off of it while putting it back in. not sure why this happened. The threads did not appear to be crossed and it was going in fine until, all of a sudden, off came the "top". The main body is still in the engine and it does not leak when the engine is running.

What to do now?

 

The post broke off? Gotta' get a new sender. I forget if it's a 12mm or 14mm head but a deep, 6 point socket is best, and keep it straight.

 

Not the post, part way down the threads. So there is still part of it in the engine.

 

I can't picture what you're describing. Can you snap a pic and upload it as an attachment?

Is the hex part of the sender still on the engine or did it snap off?

 

Hex part is snapped off.

 

A couple of things you can do. 1) Leave it alone and live without a temp gauge. 2) Remove the broken sender with a bolt extractor.

#2 is often difficult. At the minimum the distributor would have to be pulled out and then a hole drilled precisely in the center of the broken sender. Even then bolt extractors sometimes don't work. And if it doesn't work then you're stuck with a hole in your cooling system and an undrivable car.

I think the sender is brass so it might come out fairly easily. Typically when bolt extractors don't work the solution is to just drill out the hole to the correct size and tap it to the correct diameter/thread pitch. IDK what the sender's thread is, if it's tapered British Pipe Thread like the oil pressure sender or just straight metric. In any case it's not a job to be taken lightly. An automotive machine shop could do the job.

 

Thanks, these are what I assumed my options were. For now I am going to live with no temp gauge. I know the thermostat and fans work so I don't really fear the car overheating. I may take it to the mechanic that does the bigger jobs on my cars but it is not urgent.

Thanks again for everyone's help.