Overheating every second time i turn it on.

[Simong123]

I have a 2000 VT commodore.
My car over heats within 5 min's every second time i use it. But when i stop the car on the side of the road and allow the fan to cool it down then turn it back on it works fine..... I replaced the radiator fluid and thermostat on the weekend.
What else do you recon it could be? Should i buy some radiator flush from supercheap and use that?

[bhopper]

Hi there seems strange every second time it could be temp switch starting to fail , have you bleed the cooling system , also is it doing it every time your driving or every second time you start the car.

[Simong123]

every second time the car is started from cold. Na i haven't bleed the cooling system i couldn't find the dam shock sensors near the sump. But look again tonight i was hoping the thermostat would correct the problem.

[dannyssvseute]

I had something similiar on my vt it turned out to be the heater core in the dash. Could be worth checking that out.

[graham7773]

Knock sensors are about half way back along the bottom of the block on both sides. They have steel shields over them held with 2 bolts each but if you flushed the block both ways thoroughly, with the heater turned on until clean water was coming out, then added 6 litres of straight coolant plus bleed the air out via the bleed nipple on top of the thermostat housing, should be all good. GM uses a "tool" to fill the radiator can be substituted with a 2 litre coke bottle with the bottom cut off. Put it in the filler neck and open the bleed nipple, fill slowly until no air is coming out the bleed nipple, close the nipple, make sure the coolant level is up in the radiator neck and put the cap on. Take the car for a 10 minute drive and let it cool down then check coolant level. NOT WHILE IT IS HOT. Top up as needed.

[bhopper]

Hey there well i never heard of this before ,so it overheats every second time you start the car from cold ,well i guess my next question is when it overheats can you hear it, see steam under the bonnet any signs like that or just going by your gauge , also to bleed it theres a bleeder on top of the housing where the thermostat is ,if its not physically overheating it could be that you have air traped in the system and tells the sensor that is overheating when its really not overheating as the steam gives a false reading telling the fans to turn on and the gauge it is overheating when its really just air thats trapped in there i have had that happen before to me but i bleed the system and its fine give that ago and see what you get and do what what graham says.

[raskalz]

Hi.. i kinda have this problem aswell my vx was over heating pretty bad i change thermo, new radiator changed heater tap flushed the heater core, radiator, and the pipes seprately etc, now that ive bled the air out of the thermo its was goin fearly good took it for a 15minute drive came home went for another drive 10min later, 3-4 minute it over heated straight to the HOT (2nd time i started it) so i just turned the car off then turned it bak on and it was fine today it over heated again.. 2nd time again WTF.

any info? besides my friend telling me to get a FORD

[ACEMonkey]

I reckon the water pump is stuffed. Have you tried changing that and see if that makes any diffence?

[aazn]

was about to say water pump too..

get that changed before you go any more technical..

my car overheated. and i turned it off and started it up again.. went away..

next day same problem..

changed thermostat and water pump and all is good.