Water Temp Gauge Shoots into the Red for a few Secs

[Alecossy]

This topic has been discussed before but I can't seem to find a description that completely fits my issue so here we go:
A few days ago, temp in my area dropped to -2/-3 C (that's roughly 25 F). Car is parked outside and ice would start forming on it as it's normal during the winter.

Yesterday I took my car to go to Uni (it was around 7.30 AM -2 C) and a few Kms after departure, I got the "water temperature too high" message on the on-board screen. I checked the gauge only to see it flying from 70 all the way to the red zone. I pulled over, switched my car off, waited a few secs, turned ignition back on, eventually started the car and everything seemed okay. I completed the 22 KMs trip to the local University, even stopping along the way to pick up a classmate, attended classes until roughly 1 PM and drove the thing back with the temperature barely getting above 98 (fan would come on at the right time).

This morning (roughly 7 AM -/+ 1 C) my father took the car to go to work ('cause his wouldn't start <.<) and reported having a similar problem, roughly happening at the same time as mine did (When I asked him where he decided to pull over, it turned out it was the exact same spot as I did). I could safely say this only happens when the car is cold and the cooling system seems to be fully functional (thermostat, pump, belts and fan were checked and replaced less than 2 months ago, as I said in another post where I told you my fan had been rewired backwards). We both took the time to lift the bonnet and actually check the engine's temperature by placing our hands on it and I can assure you the engine was in fact colder than normal.

Based on what I read on the forums here, I can think the culprit might be a faulty sensor or the thermostat. The fluid should be fine too as the whole system was flushed when I took the car to that garage a few months ago. In any case, i'd much appreciate any kind of suggestion or your thoughts on this particular problem!

[gazza82]

Temp sensor in thermostat housing ...

Also check they have put coolant with anti-freeze in and not plain water!

[Capncol]

Have you got antifreeze in at the correct strength?

[tenpole]

Oddily it has the symptons of radweld with the overheating occuring at the same time.

[Capncol]

Ive seen this when antifreeze is too weak or missing.
The rad freezes causing the overheat due to no circulation. When you stop, the heat from the engine melts the rad and water can circulate again.

[Alecossy]

I actually had a small accident recently and had to replace my radiator (i picked up a new one for roughly 40 bucks) and never had this problem since

[Capncol]

Glad you sorted it

[tenpole]

Rad weld from previous.