Coolant problems?

[VR38]

^ you have a hi/low level indicator, it should never fall below the low mark...

 

[Dayvo]

Pull the hose out of the bottle and disconnect in from the radiator and blow through it . Sometimes they swell and become blocked with age . The pressure from the radiator will force coolant into the overflow bottle but can't be sucked back into the radiator .

 

[Wozza]

If your talking about the radiator is always about 1/4 to 1/2 cup low....then I think this is normal for the style of offset radiator cap filler on the later commies

 

[Immortality]

Yeah, I've noticed on our VX that there is always a little air in the filler neck but it doesn't seem to be using any coolant.

The other possibility is stuffed intake gaskets. Normally when the engine cools you get a bit of a vacuum in the cooling system and is siphons coolant back into the radiator from the reservoir but if the intake gaskets are stuffed it will possibly pull air in via the leak there instead.

 

[VR38]

Should never be taking the cap off to check coolant level in a system that needs bleeding, you are introducing an air lock into the system, hausing hi temp conditions.
There is a hi/low indicator on the reservoir...

 

[Wozza]

Should never be taking the cap off to check coolant level in a system that needs bleeding, you are introducing an air lock into the system, hausing hi temp conditions.
There is a hi/low indicator on the reservoir...

Air in the top of the radiator is fine it will self bleed, you should remove the radiator cap and check now and again.....Ive seen more than once the res was at right level and the radiator was bone dry...

 

[VR38]

Air in the top of the radiator is fine it will self bleed, you should remove the radiator cap and check now and again.....Ive seen more than once the res was at right level and the radiator was bone dry...

Wrong wrong wrong, just saying, Holden must have known something lol.,

FWIW if others arte going to follow this mis information, please bleed the system as per holdens service recommendations.

 

[Immortality]

A lot of air in the radiator isn't a good thing but with our VX I always find just a little under the radiator cap but can still see coolant in the filler neck. I noticed the same with my boy Legacy and both have the reservoir below the radiator where as with our old VS it would self bleed the last bit of air out not a problem because the reservoir was above the fill level of the radiator.

I've never really had issues bleeding the coolant system on the VS ecotecs, never had to point the car up hill or fit an extension in the radiator filler neck, All I ever did was fill the radiator, run till hot and top up when the thermostat opens, fit the radiator cap and top up the reservoir and add coolant as required to it and it would self bleed any small amount of air left in the radiator the next few heating/cooling cycles. With our VX it does not seem to do this as well and I can only see this been because the reservoir is well below the level of the radiator filler.

One of these days I might just convert it to the LS style with the expansion tank in the highest position. Would certainly solve the coolant bleeding issues with the L67 engine

 

[2O4TS]

As the coolant heats up some of it will flow into the reservoir and as it cools down again that coolant gets sucked back out of the reservoir. Normally a new radiator cap fixes your issue but since you have replaced that, I don't really know. Maybe a hole in the overflow hose.

I know this is the theory but how does this actually work? The cap has a spring to release 'expanded' coolant (I know.. it doesn't actually expand until it reaches atmospheric pressure but it 'wants' to) at a set pressure but as soon as the pressure drops it closes again and it happens pretty quickly. You'd be aware of this as I'm sure you've pressure tested a spring cap. They kinda 'fart' a bit at their designated pressure release and they close.
The reservoir is under neither pressure nor vacuum so how does it get back to the radiator?

In Euro cars I used to work on way back this kind of system had a flat radiator cap with no spring but a pressurised cap on the reservoir. As the coolant heated and expanded it would flow into the reservoir and as it cooled and contracted would draw from the reservoir back to the radiator. I can clearly see how this would work but for the life of me am stumped how the water gets back past a spring pressure cap. Wouldn't you need higher pressure in the reserve (which isn't pressurised at all) than the radiator in order for the coolant to flow back in that direction or am I stupidly missing something?

I don't use my reservoir. As far as I'm concerned it's only function is to stop dripping coolant on the ground if you manage to fill the cooling system absolutely 100% when cold and then catch the expanded hot coolant. Mine has never functioned as it apparently/supposedly should. Coolant never returns to the radiator and I have the luxury of cap and system pressure testers and both tested perfectly.

 

[Wozza]

Oh my..... mis information hey...not checking the coolant in the radiator on these older cars especially the vt and above where holden decided to put the res so low and hide it out of the way (nfi why) is a mistake. You wont kill or over heat the engine by removing the cap(so long as you put it back on )
Ive seen 2 vt's and my missus VX both empty the radiator and the res still had coolant in it...why because the res is below the radiator filler/vent and gravity always wins