heating problem

[lyndon_breeze]

car has 305000km on it, and when in city traffic heats up badly, i am going to chnge thermostat, and maybe the fan, the fan kicks in when turn air con on, so guessing cant be that, any ideas

[strgas]

does the fan cycle by itself ???? whats the temp like when drive along out of traffic ??? when was the rad last flushed ??? any coolant in the cooling system ??? has the cooling system been bled correctly ???

[lyndon_breeze]

does the fan cycle by itself ???? whats the temp like when drive along out of traffic ??? when was the rad last flushed ??? any coolant in the cooling system ??? has the cooling system been bled correctly ???

never seen fan cycle by itself, when cruising the car is perfect, year iver had it, never been flushed, yes there is coolant, and yes has been bled properly

[hako]

Maybe you need to explain a bit more - like what do you mean "heats up badly"........3/4 gauge reading in traffic is normal. Does it actually boil?

[Brett_jjj]

Ive owned 1 vn, 1 vr- 2vs,all v6 and they always sit around 2nd or 3rd temp gauge mark on highway,maybe lower in winter. and sitting in traffic it should climb to around half way or a bit more before the fan cycles on, and drops it back to 2nd or 3rd mark.The fan cycles off,then back up to halfway,Fan on again ,back down again.I just keeps repeating this.I noticed a big difference when I fitted pacemaker tuned length extractors,The temp on the gauge was a whole mark lower on the highway, and takes longer to heat up when sitting in traffic, ,and also noticed it used heaps less fuel.

[strgas]

If the fan wont cycle on and off then maybe you have a faulty relay or ect sensor open circuit bad earth connection ??? etc etc etc

[lyndon_breeze]

Ive owned 1 vn, 1 vr- 2vs,all v6 and they always sit around 2nd or 3rd temp gauge mark on highway,maybe lower in winter. and sitting in traffic it should climb to around half way or a bit more before the fan cycles on, and drops it back to 2nd or 3rd mark.The fan cycles off,then back up to halfway,Fan on again ,back down again.I just keeps repeating this.I noticed a big difference when I fitted pacemaker tuned length extractors,The temp on the gauge was a whole mark lower on the highway, and takes longer to heat up when sitting in traffic, ,and also noticed it used heaps less fuel.

will it basically get 7/8 to the top, fan doesnt cycle at half way, but the fan works whn i turn air con on

[hako]

will it basically get 7/8 to the top, fan doesnt cycle at half way, but the fan works whn i turn air con on

In that case I'd first check the lo speed fan relay (swap it) and if that doesn't make the fan come on at 3/4 gauge reading I'd change the coolant temp sensor (the one that tells the ECU when to turn the cooling fan on).
You can also check if this sensor works by disconnecting the sensor (the one with 2 wires) then start the engine ...after about 12 seconds the lo speed fan should come on and then about 6 secs later the hi speed should come on. (the fan is 2 speed).
Hope this helps.

[Brett_jjj]

Yeah,I agree . Low speed relay.Have a close look at the middle pin,the plastic around the pin melts slightly and relay wont work,Ive gone through a couple of these now,just swap it with the LP CHECK relay for a temp fix.Its the same one.They are around $10 each at holden.

[codie101]

hey i just took the bellmouth out of my car and reset the ecu now the car is over heating the colling fan dosent even turn on anymore and i get the same problem as lyndon it will only come on wen i have the aircon turned on plz help