Temperature gauge reading hot?

Hi,

When it overheats, can you hear the coolant boiling under the hood? I ask because we may have a faulty temperature sending unit.

Also, does this seem to happen when you are in stop-and-go traffic only, or can it happen at highway speed?

If it seems to only be in stop-and-go traffic, pay attention to see if the cooling fans are running when it is hot.

Let us know what you find or if you have other questions. Additionally, let us know if the thermostat has been replaced or not.

I will say, based on your description, it does sound like an electrical issue because it can't be overheated for one minute and slam to cold. I have a feeling it is related to the engine coolant temperature sensor (ECT), but I need more information. Let me know if it is obvious that the engine is overheating. For example, is there steam, coolant leaking from the overflow, or can you hear the coolant boiling?

I attached two pics below to help you locate the ECT. Check to make sure the wiring is in good condition and the connector is clean and tight.

Let us know.

Joe

See pics below.