Over heating when air con is on

[kyriacandro]

Hey guys my missus said she was driving the car and after a while with the air con on it started beeping that it was over heating she turned the air con off and it immediately went down what could this be ?

 

[VT&VX]

I always thought the second electric fan came on with the aircon.
You should check that both fans are working.

 

[kyriacandro]

I let the car idle yesterday for about 20 mins if i turned the air con on one fan came on so i left it on after about 20 the other fan came on so both from what i can tell are working.

But when the air con is on should both be on straight away ?

 

[kyriacandro]

From doing a bit of reading i think maybe my low speed relay may be buggered as it takes a while for the main fan to come on

 

[uniacidz]

Yeh air con fan comes on immediate

 

[VT&VX]

I wonder what your engine temp is showing on your digital guage. If it is a VT or VX, press (mode) and (^) buttons when you turn key in ignition. then press the (mode) until you see the temp.

Some might disagree, but if this is a V6 ecotec, then it is easy to take the plastic cover off the engine, unbolt the thermostat cover and remove the thermostat. You will need some gasket sealant to replace the gasket or make a temporary gasket out of almost anything, eg. Thin cardboard from a shoebox (not the corrugated box type), Aluminium off the fresh seal from Milo tin, roof gutter sealant, etc.

See if it is better.

 

[kyriacandro]

The air con fan does come on immediately when you switch the air con on but it is taking a rather long time for the drivers side fan to come on. But once you turn off air con temp gauge starts dropping immediately

 

[VT&VX]

From doing a bit of reading i think maybe my low speed relay may be buggered as it takes a while for the main fan to come on

Yes OK, problem solved.

Now enable the digital temp display and prepare to be shocked.
Then pull the thermostat out and without the thermostat try it again and work out what needs fixing.
If your cooling system still overheats just as quickly then you know it wasn't the thermostat.

 

[devilly]

check the relays, put on air con and see if they feel hot to the touch. both fans should be coming on as soon as air con is turned on. the low speed fan relay I have found overheats I only use the white one from holdens. and then do the mode and up arrow start car then press mode to get to onboard temp using this let the car warm up the fans should turn on at 104 and just when its about to go to 105 they switch on. watch what happens then you will know if its thermostat or something else going on. check all hoses for firmness once warmed up. by a brand new thermostat remove yours boil them and watch how they open and close is the easiest way to see if yours has had it. thinking your could be staying opened or closed for too long.

 

[chrisp]

Just as an aside, the late model VXs had a different fan arrangement to the earlier VXs and the previous models. I previously had a late build VX series 2 and the fans operated quite differently to the usual VT - VX arrangement.

IIRC, one fan doesn’t automatically come on with the air conditioner, instead, both fans are independently thermostatically controlled and could change speed too. I think the last VXs may have had the same fan set up as used in the VY (but I’m not sure).