Best way to bleed air from VR cooling system

[Brett_jjj]

Just have the front higher by parking on a steep slope, or even jacked up or on ramps whilst its being topped up.Then put on the radiator cap.I have a steep slope at the end of the driveway I park on to refill the radiator.All I do then is check the overflow bottle/coolant reserve bottle level for the next couple of days,just to keep an eye on it to make sure everythings ok.If this makes no difference,then definitely check that the heater tap is opening.

 

[shadetreemechanic]

Hmm, from what you're saying it doesn't sound like trapped air (or definitely not enough to cause your symptoms)
I'd be yanking out that thermostat and checking it out..sounds like its bung.
If the water pump is ok, the radiator is fine and air is bled out sufficiently, you shouldn't see temp climb when cruising on the highway.

 

[Bizmark]

Thermostat seems to be working. It's an 82c one. From dead cold, the car will heat up to the 2nd line up from C (1/4 way up), then the thermo opens up and temp falls down to the 1st line, after that it steadily rises up to about halfway, sometimes the thermo fan manages to cool it down to the 3rd line, other times it stays at 1/2 way up the temp gauge or goes slightly higher.

 

[shadetreemechanic]

This is similar to what I posted about a while ago

http://forums.justcommodores.com.au...e-seems-overheat-if-aircon-isnt-all-time.html

Run it with the aircon/thermo on all the time and see how it goes. If still no good, then I'd say the pump isn't doing its job or there is some sort of blockage restricting water flow. Or even the radiator cap, maybe it's not holding the pressure well enough (rated to 135Kpa)

 

[Bizmark]

Aircon on all the time didn't help, if anything it may have made it a little hotter. What did help slightly was heater on full and blower fan on full.

Radiator cap hasnt been changed in the last 2 flushes. What would be the signs of a failing radiator cap?

 

[The1]

radiator cap just keeps the top sealed and keeps the pressure right / controls overflow to the bottle and back into the system.

If your running a 81c thermostat it's best to get your fan cut in / out temps changed to suit the thermo.

 

[moose man]

I'd be testing your thermostat first. Take it out and boil it, and see what temp it starts to open (if it's not already stuck open).
It sounds like your temp guage is moving too much. A normally operating system will cause very little needle movement at high speed, this is the job of the thermostat.
Oh, and in my opinion 81 deg is too low, but that's just me. Whatever you do though, leave it in the engine.

 

[shadetreemechanic]

Yeah it's pretty clear now the problem is between the radiator and engine (the heater is plumbed straight into the block and is cooling the water when you turn it on)
Like mentioned before the problem MUST be the thermostat or some blockage in the radiator.

 

[Bizmark]

Oddly enough, went for another drive this afternoon, with heater control on full cold, still running a bit warm. Turned it to full hot, and temp went up a bit this time.

Btw, ive had some gurgling noises from the heater core area when i set the temp control to H. So there's airlock in my heater core, does the gurgling mean the air is going from the heater core into the block and thus casing my temp problems?