To be or not to be? (Thermostat)

[ianf]

I have heard all sorts of things from all sorts of people regarding this issue, none of which seemed to really convince me, so its over to you blokes,

I have a 99 VS Ecotec ute that has done nearly 300,000 k's without any real dramas, I have however now found a crack that was leaking water into one of the cylinders but I am pretty sure I have now sorted this with the help of a heap of Irontite, as the leaking has now stopped, I am still having some problems with over heating so once and for all want one of you guys to tell me if I should be throwing away the thermostat of simply cleaning it out???, Cheer's Ian

[FstStig]

Really Depends mate... Is it boiling? your Inlet Manifold Gaskets could be stuffed... To test your Thermostat, get some boiling water in a bucket then put your thermostat into the bucket.... If it opens up then you know its all good, if it doesn't then you know its stuffed... They are only about $10 - $12 from super cheap auto anyways.

[Harvs82]

If you are still over heating, could it be a head gasket or cracked head issue?

I'm assuming that the cooling fan is still coming on when the coolant gets hot? It should be coming on anywhere from halfway to 3/4 on the VS gauge.... If not, maybe replace the coolant temperature sensor (the one for the ECU).

Re the thermostat, definitely don't run the car without one, as the coolant can circulate too quickly for the radiator to have a chance to cool it down. If it is getting stuck shut, just buy a new one and put it in, they are only about $12 or so. The other thing could be that maybe your water pump is shot, and that coolant isn't being circulated around properly?