Radiator boils but temp gauge reads all ok

[peanutz]

I have changed water pump, thermostat,heater tap and all hoses. Took it for a drive and all seemed OK no loss of power or signs of any problems. When l got home lifted the hood and noticed the radiator was boiling. Let it cooled then took cap off and idled it until it started to boil again. There is no oil or gunk in it. What is the problem ? Head gasket leaking on the air side, Bad radiator, or cap

 

[Immortality]

Are the thermofan(s) turning on?

Change the radiator cap. The system requires pressure to keep the fluid from boiling.

 

[peanutz]

Spot on Lex , that is what l did and running smooth as silk again. One point is that my themo fan opens when coolant gets to 101. I thought it should open at 91. Thanks for your advice Lex.

 

[the_boozer]

have you bleed the air out of the cooling system? I would of guessed the thermostat opens about 86 degrees and the fans come on around 101?

 

[Immortality]

Stock thermostat for the ecotec is 195°F/90.5°C. If your thermostat is not opening to 101° then it needs to be changed. The low speed thermofan come on at 104°C unless the AC is on, then you'll find it will be running or cycling on/off when stationary to keep the AC condenser cool.

 

[peanutz]

Stock thermostat for the ecotec is 195°F/90.5°C. If your thermostat is not opening to 101° then it needs to be changed. The low speed thermofan come on at 104°C unless the AC is on, then you'll find it will be running or cycling on/off when stationary to keep the AC condenser cool.

 

[peanutz]

So what l did yesterday was let it idle until there fan kicked in. Checked coolant temp on dash display and it read 101. I thought 'humm' is that right. So l went for a bit of a drive and the thermo fan kicked in every now and again which l thought was usual. So l got home and just give it another check and the thermo fans were on and the temp read 104. That is one ? The next is should l when l turn off when thermo fan is running or should l go to aux and wait for fan to cool it off.

 

[peanutz]

Are the thermofan(s) turning on?

Change the radiator cap. The system requires pressure to keep the fluid from boiling.

Yep thermo is turning on , l do need gas in my air con. I will take it out in a little while and see the readings again. Have a new radiator cap on now.

 

[Immortality]

Just switch it off when you get to where you are going.

The exact temp isn't critical as long as they are coming on/off.

Personally I prefer they come on sooner as I think they run too hot so I adjust my tune to suit the cooler thermostat I run.

 

[peanutz]

Just switch it off when you get to where you are going.

The exact temp isn't critical as long as they are coming on/off.

Personally I prefer they come on sooner as I think they run too hot so I adjust my tune to suit the cooler thermostat I run.

Thanks, l had a high flow thermostat in it and turning on pretty regular