It happened twice, always on the same road. I was on a mountain town, and I had to hill up a bit more, before going down in the valley. During the first part the engine reached the usual working temperature, but in the middle of the descending part I realized the temperature was completely at 0 (and it was correctly indicated, since even the heating air was cold). After the first time, I added a bit of cooling fluid, but it needed just a little bit. A couple of weeks later, on the same path, the same thing happened. Someone suggested me to purge the cooling circuit from possible air bubbles (I will post here the procedure, as soon as I do it). Anyone else experiencing something similar?
Sounds like a bubble to me. There is a plugged-off high-point vent tube above the engine under the hatch. If you remove the plug for about 5-10 seconds, any air should escape. Just make sure you have a bucket handy to catch the coolant that escapes with it.
Yes. Actually, I would do it twice.. first with the engine not running to get any particularly large bubble.. and then again with the engine running.
If that doesn't fix it, you should be able to put a voltmeter/ohmeter on your sending unit to determine whether it's your gauge or the sending unit, but if it only does it on a certain situation, I think you are on the right track with the bubble theory.
I would normally say that as well, but since he said his heat also goes cold.. that leans heavily towards a bubble to me.
sounds to me like low on coolant still or air bubble so when the fronts elevated on a hill the heater core isnt getting coolant into it
