Remove Air Lock from VR-4 Cooling System

[Erni902]

Hi guys just wondering what is the proper most effective method for removing an air lock from our cooling systems?

As you all know I changed the radiator at the weekend and thought it was bled and filled properly but I gave it a bit of a thrashing on the way home sunday afternoon and after 2hrs of enthusiastic driving when I parked up the fans came on and the temp needle rose ever so slightly. (was fine the whole way back).

I am assuming I have an air lock somewhere maybe (yes ive been having issues prior to this but I have just changed the radiator so air most definitely made it into the system)

Is it simply a case of when cold remove rad cap fill rad turn engine on with heaters set to full and let idle until the air stops 'burping' out of the radiator or is there slightly more to it?

Also should I worry about running the car for too long with the rad cap off ie if I can see steam coming out the rad as its getting hotter?

[Davezj]

i bleed the cooling system by fitting a large and i mean large funnel in the top of the radiator where the cap goes, which seal to the opening. then fill the cooling system so the funnel is half full. Run the engine and rev it and let it idle, and rev it, and let it idle.
what will happen is, when the air starts coming out cooling system you see the bubbles and level of the coolant goes down in the funnel, give the top rad hose a bit of a squeeze more bubble level goes down. top up coolant . carry on doing this untill when the bubbles come out and the cooant does not go down. this means that the coolant is go to about boiling point, and all the air has come out of the system. if you have time switch off engine and let it cool down and the rest of the coolant in the funnel will get succked back into the rad as the coolant cools and contracts in size, or just remove the funel fit the rad cap and let the cooling system suck the coolant from the expansion bottle.
just remember to wash off the coolant the spills out when you you remove the funnel.

that is how i have always bleed the cooling system since had issues with over heating and a cracked raditor. and since i started doing it, i not had any issues with the cooling system.

i tried using the bleed screw on top of the thermostat housing and water just p*ssed out out of therein a fountain. you need to be able to let the air bubble out when it wants to bubble out.

[Erni902]

Cheers Dave I didnt think about using a funnel to be fair, I just watched the level in the top of the radiator and stopped when it looked as though no more bubbles were coming out. Yeah I remember reading on here somewhere that it was a PITA using the thermostat bleed screw.

Also just randomly had a thought that when I did the engine swap on the purple vr4 with gowf and mark4 we just filled the rad up and didnt even bother with bleeding the cooling system etc and I never had any dramas with that at all lol.

Ill give it a bash this week hopefully if I get any daylight to do it in.

[Davezj]

If everything is working correctly the theory says that the system will bleed itself as long as there is coolant in the over flow tank.

if there is trapped air in the system it should bubble out through the expansion tank of just get trapped in the top of the radiator. and as long as the expansion bottle pipes are air leak tight. when ever the cooling system cools down it should suck the coolant in the expansion tank back into the rad to fill it up. but if the tubes in the expansion bottle do not seal correctly or the bottle cap does not seal correctly you can just suck air back into the rad when it system cools down. even if the rad does suck the coolant back into the rad if there is not enough coolant in the expansion tank it will suck coolant and then air in as well. so it way take a couple of fills of the expansion bottle to get it fill the system completely. but that is jsut theory, it never seems to work like that for me. which is why i always manually blled the system fully.

maybe i just have laeks that let air in, but i like to air on the side of safety, belt and braces style.

[dazjb]

You guys need a coolant tower from an FTO. They sit a lot higher than the VR4 component with the bleed valve and bolt straight onto your thermostat case assembly

[elnevio]

You guys need a coolant tower from an FTO. They sit a lot higher than the VR4 component with the bleed valve and bolt straight onto your thermostat case assembly

Any more info? Pics?

What are the actual benefits?

[dazjb]

Any more info? Pics?

What are the actual benefits?

Because it will let you fill up with coolant to a point higher than anywhere else in the engine bay.

Heres mine fitted to the VR4 engine im using for the FTO VR4 conversion ...

20150313_174053.jpg

[dazjb]

Not sure why it shows a link to an image rather than just displaying it?

[SEAN-NZ]

You needed to insert an image not a link, there is an option for url when inserting image

[dazjb]

Thanks for that

Just figured out you can upload an image straight from your computer rather than trying to link to Photobucket ... duh!

[crazydriver81]

Makes no sense to me, using the FTOthingy. You need to bypass the radiator cap on the VR-4 rad and need to attach overflow bottle to the FTOthingy to make this work. Will defo not help with bleeding the cooling system properly.

[dazjb]

I thought this would have helped with the bleeding issues you guys have with your bleed point being so low on the thermostat housing. I didnt realise your expansion tank was in a different place to the FTO though (which is behind the nearside strut). With the FTO tower you have a point higher than anywhere else in the system to fill with coolant .. I have never had problem with bleeding and I have drained my coolant more times than I can remember.