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Correct way to burp a radiator


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#1 _judgelj_

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Posted 11 November 2014 - 11:16 PM

Just wondering how people go about burping/bleeding their radiator. I usually find myself working on older cars and ill just run them with the cap off, let the bubbles come to the surface and top up until the fluid is still (no air). This usually involves a bit of fluid overflowing but i assume that is just expansion and air escaping. Is this bad? Should i not allow it to spew? Should i fill it until the fins are just covered next time?

The reason i ask is i had to do this with a VE and it was all going smoothly (little bubbles popping) but it started to really spew out at one point and my mate started sooking so i turned the car off.



#2 sibhs

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Posted 11 November 2014 - 11:36 PM

I fill up slowly, stopping and squeezing top and bottom hoses. Took about 2 hours.
When I filled up too fast the first time it spewed boiling water when cap was off. I think that means there is an air lock which got very hot.

#3 Bigfella237

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Posted 12 November 2014 - 02:27 AM

It depends on the type of cooling system...

 

With the old (circa 1970's and older) systems that just had an overflow hose running down the side of the radiator, we used to fill the system then run the engine with the cap off until the thermostat opened, then top up as required, replace the cap and re-check again when the engine is cold.

 

The next generation with the overflow bottle and two-way cap you can generally fill the radiator and the overflow bottle, install the cap and then run the engine, you should see any air within the system come out as bubbles in the overflow bottle once the thermostat opens, the cap should then suck any extra fluid it needs back into the radiator once the system cools down.

 

With the third type (as in VN Commodores onward) the overflow bottle is actually a pressurised part of the system and is mounted higher than the engine or radiator so any air within the system should circulate and find its way into the reservoir.

 

Three important notes:

 

1) Some vehicles actually have bleed nipples in the cooling system at places where an air pocket can get trapped (like the top of the thermostat housing or inlet manifold), generally speaking you will never be able to remove an air pocket from these places unless you use the bleed screw(s).

 

2) Remember the heater core is part of the cooling system too, you need to turn the heater temp control to hot and let the water circulate through the heater hoses too or you will introduce another big gulp of air next time the missus complains about having cold feet.

 

3) NEVER POUR COLD WATER INTO A HOT ENGINE! Things that are expensive to fix tend to warp and split when you do this.



#4 _bathurst-racer_

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Posted 12 November 2014 - 05:30 AM

I usually remove the thermostat and fill the block, replace it and then top up via the radiator cap/overflow bottle.



#5 76lxhatch

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Posted 12 November 2014 - 05:32 AM

With the radiator cap at the highest point you really can't go too wrong no matter what you do.

My favourite trick for vehicles that have a higher point with a bleed screw is to up-end a coke bottle in the fill cap - with the bleed screw removed completely just squeeze the bottle until coolant comes out the bleeder. Then its full enough that you can warm it up and simply crack the bleed screw slightly to get the last little bit of air.

I believe only VN series 1 V6s had the pressurised bottle, they had no cap in the radiator.

#6 _mello92_

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Posted 12 November 2014 - 06:27 AM

With the VE, fill it up then install the cap, run it up to operating temperature, let it cool and top up as required.

I've only had to top them up once.

#7 _judgelj_

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Posted 12 November 2014 - 09:42 AM

Ok makes a lot of sense. Ill just install the cap with the VE.

 

I just needed to be able to understand it in my head. Usually when i do it the messy way, say for instance with the torana, it will just rise and spill until the water level no longer changes. This tells me it is done. So why was the VE literally spewing out water like a geyszer? Big air pockets? It was bloody hot too.



#8 _GMH-001_

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Posted 12 November 2014 - 11:07 AM

falcons do the same thing, not 100% sure why. Another simple trick too is jack up the front of car to get rad cap even higher than engine. Approx 96 celica you had to do this as there was no bleed screws and an absolute pita to bleed properly. Filling engine with hot water will help open thermostat and bleed quicker/easier too



#9 UCgazman

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Posted 12 November 2014 - 12:50 PM

I've got a T3 VW caravelle, engine in the back, radiator in the front - try bleeding that, its a prick of a job!



#10 _judgelj_

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Posted 12 November 2014 - 08:27 PM

falcons do the same thing, not 100% sure why. Another simple trick too is jack up the front of car to get rad cap even higher than engine. Approx 96 celica you had to do this as there was no bleed screws and an absolute pita to bleed properly. Filling engine with hot water will help open thermostat and bleed quicker/easier too

Yeah its strange. As for the types that just overflow a bit whilst bleeding, thats just big air pockets escaping right?

 

I've got a T3 VW caravelle, engine in the back, radiator in the front - try bleeding that, its a prick of a job!

Screw that!



#11 _GMH-001_

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Posted 12 November 2014 - 10:57 PM

yes it is, but somehow it's somethin with the bypass hoses etc and for some reason seems as though it's boiling while your trying to bleed. Dunno the exact cause but them I just put cap on, let it get hot, cool down and top up (as previously mentioned)

 

 

I've got a T3 VW caravelle, engine in the back, radiator in the front - try bleeding that, its a prick of a job!... sounds like a real biatch lol



#12 UCgazman

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Posted 12 November 2014 - 11:50 PM

^You have to use the ultra pricey VW G12+ coolant in it too, because they have really thin head studs that sit in the water jacket and once they get a bit corroded they snap...



#13 _GTR_069_

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Posted 15 November 2014 - 06:38 AM

I have a 65 VW Splitty Ute, can't find the radiator lol



#14 UCgazman

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Posted 15 November 2014 - 12:33 PM

Its behind the flux capacitor....



#15 _big jack_

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Posted 17 November 2014 - 12:11 PM

Sorry for the thread steal, I want to flush the cooling system on my VX V6 Commodore could someone go thru the procedure with me. And also what coolant to use?

 

Thanks, John.



#16 r2160

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Posted 17 November 2014 - 01:21 PM

Found this, hope it helps: http://forums.justco...-v6-1999-a.html

 

Otherwise, get the radiator, pop it gently over your shoulder, and just gently pat it until all the air comes out . . .

 

cheers

Glenn



#17 _big jack_

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Posted 17 November 2014 - 04:34 PM

^That's funny :badabing:



#18 _judgelj_

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Posted 17 November 2014 - 05:14 PM

I'd pull of the bottom then top hose. That will get rid of most of it. There should be a bung on the side of the block somewhere but im not sure.

Apart from that shove a hose in he radiator and flush that out. Then refill with a good quality green coolant.



#19 _mello92_

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Posted 17 November 2014 - 08:02 PM

Sorry for the thread steal, I want to flush the cooling system on my VX V6 Commodore could someone go thru the procedure with me. And also what coolant to use?

 

Thanks, John.

 

 

These things like to have an air lock so there is a bit of a trick.

 

As above drop the bottom hose, then remove one of the heater hoses from the side of the engine and with the heater on, poke a garden hose in both ways until the water coming out of the bottom hose is clean. Remove the radiator cap, thoroughly inspect the seals for damage, if in doubt, replace it. Seem to be going through a lot of caps lately at work, must be the in thing. Poke the hose into the bottom of the radiator and flush it backwards then forwards until clean.

 

Refit bottom hose, then remove engine cover and locate the bleed screw on the thermostat housing. Unscrew bleed screw and remove entirely. Add appropriate amount of coolant to radiator, you will note that some water may spill from the open heater outlet or hose. Ask someone to hold their finger over the heater outlet on the engine while you poke the garden hose into the heater hose and slowly backfill the system. Refit the radiator cap when coolant/water spills out and do the same with the bleed screw. 

 

Remove hose and quickly refit to the engine, ensure all clamps are tight etc ensure the recovery bottle is full or fractionally overfull, wont hurt.

 

Pressure test the system if you have access to such equipment, use distilled water if you want.

 

Dont use SuperCheap/Calibre crap, any other general brand name coolants are fine.

 

Refit any other components, run engine at 1500-2000rpm with heater on until normal operating temperature is achieved. Inspect for leaks. Let it cool then top up the radiator if required.



#20 _big jack_

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Posted 17 November 2014 - 08:11 PM

Thanks Carmelo, that's exactly what i needed  :spoton:

 

Cheers, John. 






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