Over heating when air con is on

[VT&VX]

by a brand new thermostat

.... as in BUY
Spend some money, replace parts and you will eventually fix it.

Leaving a questionable thermostat in, can damage stuff and cost more.
Excessive heat, means more pressure on hoses and radiator and gaskets and radiator cap.
So change it or at least take it out temporarily.

 

[kyriacandro]

Its a brand new thermostat brand new radiator cap heater tap is only 6 months old if that. Radiator maybe 2 years old tops that's why im thinking it's the low speed relay ill have a play with it tomorrow. Can you get the relays from repco ect ?

 

[Lex]

Hi
Anybody heard of a water pump?

 

[devilly]

from all the mucking around i have done i found genuine holden relays to last the longest and also not over heat where it feels like you can boil and egg on it. my thermostat was only a few months old and failed. the reason i didn't think water pump was because it only over heats when air con is on.

 

[kyriacandro]

Same reason i was not thinking water pump because it takes a while for it to actually over heat and if you turn the air con off immediately it goes down to normal

 

[Lex]

Same reason i was not thinking water pump because it takes a while for it to actually over heat and if you turn the air con off immediately it goes down to normal

The engine runs alternator, power steering pump, water pump, not over heating. When you turn the a/c on, you put more load on the engine, & what happens? It over heats. Turn off a/c & engine cools down. Why? Load taken off engine.
Possibly the vanes on back of w/pump are corroded? Not pumping efficiently?
Just saying my 2 cents.

 

[VT&VX]

Turn off a/c & engine cools down. Why? Load taken off engine.

Yes, as he says. It seems your cooling system can't handle the extra load. Did you check that your new thermostat was able to Fully Open or did you see it opening a bit and decided it was good to go in.
Take it out, run the car without it and see what happens. If no change then Water Pump needs checking.

 

[kyriacandro]

Yes thermo fully opened

 

[VT&VX]

Well you don't seem keen to try running it without the thermostat (in order to rule out opening too late or closing too early), so that means you have to remove the water pump and hope it is stuffed because you went to the trouble of removing it for that reason.

PS, clean the crap out of your aircon and radiator fins and between both because there may be hardly any air flowing through both of them.

Use a hose and push crap through carefully. DON'T USE A HIGH PRESSURE GERNI ON THE RADIATOR FINS. IT WITH SQUASH THEM DOWN.

 

[kyriacandro]

Changed the water pump today the inside of the old one was absolutely stuffed. Did the temp test to low speed fan turns on at 104. Pretty sure that's what it was guess ill know when we take it for a long drive with air con on