Vt commodore temp rising then dropping quick

[lynx2093]

Hey guys I'm having a problem with the temp of my car
About a month ago i was driving on the beach and my belt slipped off
My temp went all the way to H

Now since then I'll be driving and the temp will rise to H and then drop back down to had way after about 10 seconds

What could be causing this?

Thanks

 

[Jxfwsf]

Bleed the cooling system correctly when refilling, sounds like air trapped in the system.

 

[Tsunamix]

May also have burnt the thermostat rubber, or have a piece of crap dislodged at high temp (Under high steam pressure) that is occasionally partially blocking the system limiting flow

 

[mpower]

Bleed the cooling system correctly when refilling, sounds like air trapped in the system.

my money is on this.

 

[TheBigBopper]

hey is the radiator pretty old blocked up and in need of replacement and the car is actually over heating and the up and down of the gauge is the thermo coming on then being off maybe?
What about just a temperature sensor pulsing up and down erractically cause it been in there from factory and need throwing cause its posessed!
Next time that gauge goes right up pull straight over and jump straight out lift the bonnet and determine for yourself if the motor is really overheating ie it looks like its about to explode and steam and hissing bubbling? ive been tricked on this one before
finally get the front end higher in the air say on ramps rip out the thermostat but it back together empty start the car open the air bleed screw right open pull the throttle cable at a good high enginge speed for a good time and dont close that screw until your positive there just couldnt be any more air. finally turn off the motor take off all the high tension leads you just drown while bleeding and give the connectors a bloody good blast off wd40
in a day or so with no thermostat bottle neck if shes still overheating the 1st cheapest easiest option a bloody good chemical cooling system and go for a good drive not just idle on the drive then finish the job as required.
still overheating time fora new bigger radiator...
still overheatng sell it! hehe...