How To Flush A V6 Cooling System

[JoshSvc]

I believe that it what is recommended, 5 litres of straight concentrated coolant and the rest with water, thats what i did and my car never got hot.

 

[hustlin420]

nice guide and good advice

 

[Bizmark]

Ok i did a cooling system flush (though did not run the engine during this process) I followed most of the instructions as posted by Chridda, but instead of leaving the top radiator hose off when filling the system with coolant, i had everything connected and had a drink bottle stuck into the radiator filler neck. I also had the overflow bottle lid plugged into the overflow bottle. And ive installed an 82c thermostat

When i took the car for a test drive i could hear a heap of gurgling noises coming from behind the dash and it seems i have airlock in the system again (temp is hitting the 1/2 way mark even while the car is moving) Is there a reliable way to get rid of the air without flushing the system all over again?

 

[JoshSvc]

That is what the air bleed screw is for, its on top of the thermostat housing.

 

[Epalmer]

Mm, the bleed screw wouldn't be there if it wasn't meant to be used. Did this a couple of weeks back, worked great! Thanks for the write up! +rep

 

[JoshSvc]

I replaced the radiator in the girlfriends vs only 2 days ago, Took me under an hour to have the whole thing done. I do agree though that lifting the front end even only afew inches does help, but isnt totally necessary. Make sure you have a good thermostat in it, the radiator is clean and use the right 50/50 mix of coolant and water and you will have trouble free motoring.

 

[bumskins]

Attached is a copy of the cooling system refilling instructions from the genuine Holden workshop manual. From memory the instructions were from the VR workshop manual however you should be able to use them on any of the Holden V6's based on the Buick V6 block.

A couple of people here have already mentioned the ability to fit an attachment to the top of the radiator in order to assist with the bleeding process by making the fill point the highest point in the cooling system. As mentioned, Holden did make a special tool for this however no one has one obviously!

I've been told previously by Holden mechanics that the best way to achieve a similar result is to chop off a length of old V6 radiator hose (usually one you've just replaced) and jam it in the radiator filler neck. Oddly enough it fits perfectly and doesn't leak at all!

From here you would use the standard workshop procedure of filling the attached hose nearly to the top and running the car whilst periodically opening the bleed valve on the coolent outlet at the top of the motor to release any trapped air. Whilst the car is running (with the interior heater on max) you should see bubbles occassionally floating to the top of the radiator attachment.

I personally, run the motor until hot so that the thermostat has a chance to open and release any last trapped bubbles of air however I'm not sure how necessary this is because when using this technique most of the air seems to rise to the surface fairly quickly! Parking facing upwards on a hill will obviously raise the attachment higher still if you really want to get pedantic. Once your no longer seeing any more air coming coming out of the system remove the radiator attachment (you will spill some coolant doing this, just wash it off) and replace the radiator cap BEFORE turning off the engine.

I've also attached pictures how the radiator attachment should look in practice.

 

[Hot-Rod]

Has anyone noticed supercheap and repco no longer stock the castrol 5L bottles. Now they sell the silly 2.5L bottles. Very annoying.

 

[bumskins]

Last time I was there, Repco was still selling Nulon Long Life coolant concentrate in 5L bottles.

Just a bit of related info on the topic of cooling systems...if you've ever wondered why manufacturers recommend you only mix distilled water into your car's cooling system (most people seem to neglect this part) it's because regular tap water is over 1000x more conductive than distilled water as a result of the impurities. Hence your car's radiator (amongst other things) will experience a much higher electrolytic effect when filled with tap water. See the table below for more info.

Table of Aqueous Conductivities
Solution µS/cm
Totally pure water 0.055
Distilled water 0.5
Domestic "tap" water 500-800
Sea water 56,000

Note: 'S' is the measure of electrical conductivity in 'Siemens' commonly measured across a span of 1cm in fluids.

 

[Orpheus]

Hi,

Great Thread ChRiDDa,

I did this yesterday, It too me ages, as this is the first time I've done anything like this,

I do have some question if you care to answer,

Step 5

"Place the top radiator hose back over the housing, and remove the bottom radiator hose from the radiator snout. Turn the garden hose on and place it in the top hose "

When i did this water was just going through the radiator out the bottom hose, So what i though you meant was this, I Plugged in the bottom radiator hose, Plugged in the top radiator hose but left it unplugged from the housing, I then put the garden hose in the top hose, started the car and watched the water come out of the housing,

Is this what you meant?




I did this all because my mechanic said i may have a broken head. I have just filled it with tap water, no coolant is it ok to run it like this for the next couple of days or a week?

My mate said it would be easier to see if it's oil if its just water and it wouldn't do any harm.

When i cleaned it the water was really dirty, i don't know if its just sludge or oil, I was also planning to flush it one and then use the radiator flush and do it again since it was so dirty but i didn't have time so, I just flushed it all with clean water



The thermostat i got for my VT - is Dayco Part No: DT22b-BP and it had a rubber seal, but the one i was replacing did not and was sitting flush, If i used the rubber seal it wouldn't sit flush so i just used the gasket then on top the thermostat, Just like it was on the old one, So i think the gasket will seal the thermostat + housing? Does this sound right?



I tried really hard to put in the new thermostat the same way the old one was, but i don't know if it is 100% right as the old one didn't have any markings or anything, Is there anything i should be looking for when installing a thermostat, The old was was like diagonally in there, I am referring to the line bit where you can grab onto it.

When i was done i filled up the radiator, started the car, left it running for about 20 min and kept topping it up and filled the overflow to max, then released the bleeder till it was pouring water, the car seem to be running cooler now.