Holden commodore sv6 ve 2008 loosing coolant

[lmoengnr]

Radiator cap

You'll need to bleed the system every time you pop the radiator cap off...
V6's are problematic to bleed properly. You should be checking the coolant level via the dipstick in the overflow bottle.

 

[rambunctious]

You'll need to bleed the system every time you pop the radiator cap off...
V6's are problematic to bleed properly. You should be checking the coolant level via the dipstick in the overflow bottle.

Quite a number of times I have read the idea of bleeding the air after removing/replacing the radiator cap, (Fu man mentions it all the time) and I always check both the radiator bottle dip stick AND the radiator cap, in fact I top up via the cap (not topped in over 12 months) and I have never ever bled the system after removing/replacing radiator cap, and I have never ever had a problem.
The cap is, if not above the radiator, then certainly level with it, and, as the OP has stated, once the bubbles have gone (air rises/fluid drops) then for all wants and purposes, the system should have no air in it.
If I do top up I do it when the engine is cold or at least not hot/under pressure.
When I replaced the radiator a few years ago, I bled it through the bleeder nipple on the radiator then topped up through the radiator cap.
Just saying.

 

[greenacc]

Quite a number of times I have read the idea of bleeding the air after removing/replacing the radiator cap, (Fu man mentions it all the time) and I always check both the radiator bottle dip stick AND the radiator cap, in fact I top up via the cap (not topped in over 12 months) and I have never ever bled the system after removing/replacing radiator cap, and I have never ever had a problem.
The cap is, if not above the radiator, then certainly level with it, and, as the OP has stated, once the bubbles have gone (air rises/fluid drops) then for all wants and purposes, the system should have no air in it.
If I do top up I do it when the engine is cold or at least not hot/under pressure.
When I replaced the radiator a few years ago, I bled it through the bleeder nipple on the radiator then topped up through the radiator cap.
Just saying.

Agree, how can air enters the system via the pressure cap just by unscrewing the cap?
That would mean you have to bleed your brakes every time you take the cap off the master cylinder. Air floats, it doesn't sink..

 

[krusing]

Put some Red Glycol (coolant) in it, (if it hasnt already)
and get it pressure tested,
Then you will possibly see where its leaking.

I'm tipping its the Radiator,
as VE's have a tendency to leak at the bottom, on the back of the radiator behind the Fan Shroud,
You can smell it, but cant see it, as it dries (evaporates) with the fans, heat that is produced.

 

[Fu Manchu]

Yes and once all the air is out bubbles stop but it's still goes down

That means the air is not out. It has to be done with a bleed bucket attached to the filler. Doing it with just the cap off is no where near ideal.

 

[Fu Manchu]

Agree, how can air enters the system via the pressure cap just by unscrewing the cap?
That would mean you have to bleed your brakes every time you take the cap off the master cylinder. Air floats, it doesn't sink..

The difference is that it should be under vacuum. The comparison to the brakes is you are checking the reservoir in the system. With the cooling system, you should be checking it at the reservoir also. That’s the comparable assembly to the brake fluid reservoir. The system remains under vacuum.

If you crack the brake hose on the calliper to see if there is fluid in there, that is the same as opening the filler cap which is midway to the system under vacuum. You are letting air into the system.

Checking via the filler cap should only be done infrequently if there is an actual reason for it. That reason shouldn’t be regular inspections of the level. Thats what the reservoir is for. Just like in the brake system.

 

[rambunctious]

Yes and once all the air is out bubbles stop but it's still goes down

Which means you have a leak so you need to locate the leak.

 

[Fu Manchu]

Vacuum filling the system is the best way to do it. All air is removed first. The system is left for 5mins under vacuum and the vacuum should be more or less the same, indicating system integrity is good. Then it’s filled under vacuum and requires zero air bleeding. It’s done in minutes. Fill the reservoir and maybe check the coolant dip stick once or twice in the week ahead.

 

[sv6VEcommodore]

That means the air is not out. It has to be done with a bleed bucket attached to the filler. Doing it with just the cap off is no where near ideal.

Yes so I bleed the system and it was fine put cap back on and by the time it was cold went back down i then topped back up and went down again now not even starting trys to but cuts off, would that mean its a cracked head/ gasket?

 

[sv6VEcommodore]

Which means you have a leak so you need to locate the leak.

Yes so I bleed the system and it was fine put cap back on and by the time it was cold went back down i then topped back up and went down again now not even starting trys to but cuts off, would that mean its a cracked head/ gasket?