Overheating since replacing new radiator

[lovemyholden]

My holden VS has been perfect temperature wise since I bought him 5 years ago. I recently replaced the radiator (it spat the dummy and the engine overheated, had to have it towed home) and ever since then, he heats up much more than he used to when I am sitting in traffic. Doesn't heat up during normal driving, only when the car is idling at lights or in traffic. The temp gauge goes up to three bars from the red line.

I have replaced the thermostat gasket, the thermostat, the temperature sender and added new antifreeze.

The fan isn't turning on when it used to, but it does turn on at a higher temp.

Any ideas, anyone?

[GeorgeB]

hey mate, its nothing to worrie about mine does it too and im sure it happens to plenty others. APPARANTLY thats how they were designed. The fan won't kick in until it hits about 3 quarters. When your idling or in traffic the reason it gets so high is because there no air intake goin to the radiator. But when your drivin at normal speeds there is air intake so its cooling down your radiator.

I'd rather have my fan running all the time and i have seen it done before. ppl just get some modifications to the electricaL connections. my mate got it done not too long ago. Its a simple job.

But thats how they were designed so you wont have any drama's.

NExt time your in traffic and the temp is starting to rise, put the Air Con on, and you will find that the temp won't rise even when your idling or in traffic. Thats because when the A/C comes on the electric fan also comes on...

So its up to you champ, get it modified if you want, but really when u think about it, if holden designed it that way then it means theres nothing wrong with your radiator.

Hope this helps
Let us know how it goes...

[BlackVXGTS]

Did you open the coolant air vent valve to purge all the air from the cooling system?

[VT-565]

check the contacts in the plugs for your thermo fans...should be at the drivers side top of the radiator somewhere...you could also check the temperature sender too and make sure it is clean and hasnt got any build up on the sensor....

[lovemyholden]

Hello, thank you for responding,

Yes I did open the valve, and it vented. I was guided by the mechanic who installed the new radiator. He forgot to do it, rang me and told me what to do over the phone.

I think it may be the sensor behind the thermostat needle in the dashboard. I had no idea that they existed, but they apparently do. Some commodores, my kind, have had resistors fitted to control the overactive needle sensor.

That doesn't make sense to me, but I'm just looking for the right answer.

I have to hook the car up to the computer, monitor the engine temp as it idles, and if the temp is good, then it's possibly the needle in the dash.

[ads72]

where is the coolant air vent valve

[feistl]

Its right on top of the engine, where the black pipe runs from the engine to the radiator. There is a little screw ontop. open this up till its a constant stream of water/coolant coming out. remember its going to be how