water sloshing behind dash/in engine bay

[yezzzah]

Howdy legends

I haven't had my VY V6 long but have run into an issue with it overheating. Twice. I have since flushed both the engine and radiator of old coolant using water and it has been filled up with new coolant and bled of air.

Even though I'm sure the air has been purged from the system, I am still hearing a lot of sloshing in/around the engine bay/ dash, please note that the heater and aircon in this car have never worked properly while I've had it (seems to only blow ambient air and makes a lot of noise but not a lot of air gets pushed around) and no I have not flushed the heater core as I'm not quite sure how. Has anyone else had this problem? I've read about there being water in people's door sills but I'm quite sure this is not the case. The only other symptom I have read about so far is a leaking heater core, in which case I am not having the common symptom of a wet passenger-side floor.

Hoping somebody has been in this situation and could possibly shed some light, cheers

-Update,
Thanks so much for your replies, I've found them all useful and appreciate you guys for sharing your knowledge.
I've been super slack at getting this sorted but am going to start off by getting a new radiator cap because as I forgot to mention -My coolant overflow is currently always full so I think there may be a problem with one of the valves in it not creating a vacuum to suck the coolant back into the system.
Will do another update as this progresses or the problem is resolved.
Thanks again, Wizards!

 

[Fu Manchu]

When emptying, flushing, filling, and bleeding have the heater set to hot.

Have someone check the heater tap actuates when the temp is adjusted.

The heater tap under the bonnet could be stuffed.

I would drop the coolant and remove the heater hoses and flush the heater core on its own. See what comes through. Make sure it’s not blocked.

Other cause for the heater not blowing hot could be the evap core and heater having lots of grot in them.

Remove the wiper cowl. Give it all a good clean out. Especially where the air goes into the cabin. Mark wiper position with some tape on the windscreen before removal.

Remove the blower motor. Then you can get your hand up into where the evaporator is and take a photo with your phone at what it’s like in there. Might need a clean if it’s mostly blocked. That will be limiting air flow.

If the air flow won’t change from demist to feet or face etc, explore replacing the actuators, which in pre VE are vacuum operated.

 

[Bigfella237]

And check the plenum drains are clear while you're in there.

The other possibility is if the A/C evaporator drain hose is blocked (damn wasps love to build nests in them)?

 

[87VLCALAIS]

Been down this track.

To start with I had random overheating which I eventually fixed by replacing the radiator.

Then I was getting a noise like you describe. Bled the air from the bleed screw on the thermostat housing. The bubbling/gurgling noise kept coming back.

In the end I came to the conclusion it was the gasket on the blanking plate on the rear of the engine leaking water. I had green water (the anti freeze was green) dripping from the bellhousing area.

My theory was the water would leak past the gasket and when the engine cooled instead of sucking water in from the overflow bottle, air was sucked through the leaking gasket. A theory which was supported when I back off the radiator cap to the first step and the air bubble noise went away. The green water stopped leaking at the same time.

I'm about to find out whether my theory is correct. The gearbox is out having the bearings replaced and I'm getting the blanking plate replaced at the same time.

Try bleeding the air at the thermostat and backing off the radiator cap and see what happens.

Edited to add:

My heater was also hit and miss with how hot it would get when the air bubbles could be heard.

Also take the plastic cover/shroud off the top of the radiator core. You might be surprised/shocked at how much crap is trapped between the radiator core and the air con evaporator core.

I replaced my heater core a while back and based on my experience I doubt it's blocking the air flow. It would be worth checking that you can hear the vents moving when you rotate the control knob on the centre console. It is possible they aren't working properly.

There is a vacuum reservoir which should allow the air valves to be moved even when the engine isn't running making it easier to hear them moving.

 

[Fu Manchu]

The bleed screw is grossly insufficient for removing the air. It does assist refilling the system. It doesn’t bleed the trapped air out.

The only two ways to have no air is to vacuum fill the system or bleed the system with a bleed bucket attached to the filler, run the car through two or three thermostats openings. This was taught to me by a Holden technician back when I had my VP which had similar problems being discussed here.

Not had a problem since.

 

[87VLCALAIS]

The bleed screw is grossly insufficient for removing the air. It does assist refilling the system. It doesn’t bleed the trapped air out.

The only two ways to have no air is to vacuum fill the system or bleed the system with a bleed bucket attached to the filler, run the car through two or three thermostats openings. This was taught to me by a Holden technician back when I had my VP which had similar problems being discussed here.

Not had a problem since.

Yes, it will take at least a couple of heat/cooling cycles to be sure all the air is gone. I use a short length (150 to 200 mm) of foam tube stuck ino the radiator filler neck to ensure a head of water well above the bleed screw. The OD of the foam tube is slightly more than the ID of the filler neck ensuring a tight fit to keep the tube in place while the coolant is being added and the air bled.

Be wary of air being trapped that ends up in the thermostat area after your first bleed attempt. There may not be enough heat transfer to open the thermostat and you will end up with overheating. This has happened to me once. I was able to stop promptly and carefully loosen the radiator cap while covering it with a towel. Loosening the cap released the trapped air.

 

[Fu Manchu]

This was written for VZ-VF but just as relative to other previous models.
I’ve included video and the tools used.
https://forums.justcommodores.com.au/threads/vz-ve-vf-alloytec-cooling-system-repairs.279976/

 

[87VLCALAIS]

Good write up

 

[HSV126]

The bleed screw is grossly insufficient for removing the air. It does assist refilling the system. It doesn’t bleed the trapped air out.

The only two ways to have no air is to vacuum fill the system or bleed the system with a bleed bucket attached to the filler, run the car through two or three thermostats openings. This was taught to me by a Holden technician back when I had my VP which had similar problems being discussed here.

Not had a problem since.

Second this, Vacuum filling is a game changer on these cars