Erratic temperature gauge

Every once and a while, my 1998 honda accord’s temperature gauge jumps from cool to hot to cool in a matter of seconds. It happens every other time I drive to work (my drive is about 40 miles each way and somewhat hilly).

I brought my car in to have it inspected. According to my mechanic, the temperature sensor was faulty so I had it replaced. My mechanic also looked at my coolant and noticed it was blue (eek! suggesting that windshield wiper solution had been added to the wrong resevoir by a different mechanic the week earlier when I had my oil changed and fluids checked.) So, my mechanic also flushed my radiator and replaced my coolant.

Here’s the problem: despite all of these fixes, my temperature gauge is still acting erratically.

Any thoughts?

temperature gauge jumps from cool to hot to cool in a matter of seconds.

You may be looking for the wrong problem. Not every gauge that looks like an analog gauge is, many are digital with only two or three states - Cold-Warm-Hot. Unless you know that it really is measuring and displaying analog results, my concern would be why is it going to HOT and not why it is doing it fast. As you getting any other indication of it being too hot?

Thanks so much! That is a really helpful comment.

Here are some observations:

  • the coolant level appears to be fine although the reserve does have some liquid in it
  • the fan kicks on normally
  • I haven’t observed any steam
  • I believe the gauge tends to jump to H when I am going up hill (sometimes it will stick there for less than a second, sometimes for 5+ seconds)

Thanks again, Joseph!

Had the same thing on my 88 Accord Lxi. The connector that attaches to the temp sender was loose. Disconnect and crimp it down a little with small pliars or your teeth.