Technical Airlock on Mark 2 cooling system

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Technical Airlock on Mark 2 cooling system

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Jan 20, 2015
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Hi.
Had a nightmare today. Went to change my daughters antifreeze and as I was bleeding the system the bleed valve on the heater hose snapped off. I managed to temporarily run a self tapping screw through the sheared off head into the remaining part of the screw in the housing and used plumbers sealer to at least get the car mobile. It seemed to work, at least for the moment hopefully anyway.
I then refilled the lost coolant and bled the only other outlet on the radiator then put the expansion tank lid on and started the engine. It took about 20 minutes before the fan came on, the heater blew out hot air and the top and bottom hose became hot. So far so good. I let the car cool a bit and topped up the coolant. I then restarted the car and let it run for another 20 minutes or so but this time the fan wouldn't come on and the top and bottom hose felt soft and didn't get hot.
I took the car for a run and the heater continued to blow hot and the temperature gauge stayed where it should in the middle. When I opened the bonnet the hoses were still cool and soft.
Am I imagining there is air in the system as the car is running fine? If there is air how can I get rid of it?
Also when I replace the broken heater bleed valve is it, like I suspect, one whole piece connected to the four hoses and is it easy to replace?
Your help would be much appreciated.
Thank you.
 
Well they were both just lukewarm.

No the screw thread on the nipple broke off inside the housing. I was just left with the top part, the thumbscrew.

Thanks for the guides. I will read them later.
 
My car has been running before I bought it with a garage fitted self tapping screw fitted to that same bleed fitting. No problems at all other than for piece of mind I replaced the small screw fitted with a thicker one.

The fitting the bleed screw is on comes complete with the 4 hoses and is not worth replacing for the sake of the bleed screw. On my car one of the hoses is totally stuck onto the heater and will have to be cut off to avoid breaking the heater.

I have proven on my car time and time again that if the top bleed screw is not opened that all of the air will eventually be removed from the car after about 4-5 days.

If you cannot hear water gurgling noises coming from your dashboard when you are sitting inside then you do not have air worth worrying about in your system.

When it is around 0C when my car is idling and the heater is on hot with the fan going, the car will not come up to working temperature - it stays about one quarter on the temperature meter.

These cars have an externally circulating supply of water going from the back of the engine via the heater at all times even in summer, and then back to the front of the engine so plenty of the heating available is not passing thru the heater or the radiator in normal operation so in colder weather it does not sound so unusual the cooling system is not getting very hot. Only if the temperature guage does not go to half way and the radiator hoses are cold would it suggest you have a problem with the thermostat being stuck open.
 
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Thanks very much Judderbar. I think I will leave the self tapper in situ then in that case. I thought it looked like hassle getting to all the jubilee clips anyway.
I only did the job yesterday so I will give it a few days first to see what happens. I was really puzzled why the hoses were hot and quite firm when I first filed up and ran the car then they went limp and cooled after switching off then restarting again.
Reading online it seems that this bleed screw seems to break a lot.
 
My car has been running before I bought it with a garage fitted self tapping screw fitted to that same bleed fitting. No problems at all other than for piece of mind I replaced the small screw fitted with a thicker one.

The fitting the bleed screw is on comes complete with the 4 hoses and is not worth replacing for the sake of the bleed screw. On my car one of the hoses is totally stuck onto the heater and will have to be cut off to avoid breaking the heater.

I have proven on my car time and time again that if the top bleed screw is not opened that all of the air will eventually be removed from the car after about 4-5 days.

If you cannot hear water gurgling noises coming from your dashboard when you are sitting inside then you do not have air worth worrying about in your system.

When it is around 0C when my car is idling and the heater is on hot with the fan going, the car will not come up to working temperature - it stays about one quarter on the temperature meter.

These cars have an externally circulating supply of water going from the back of the engine via the heater at all times even in summer, and then back to the front of the engine so plenty of the heating available is not passing thru the heater or the radiator in normal operation so in colder weather it does not sound so unusual the cooling system is not getting very hot. Only if the temperature guage does not go to half way and the radiator hoses are cold would it suggest you have a problem with the thermostat being stuck open.

i always remove them by sticking flat screwdriver in and prying it apart, it takes some time, but i get them off undamaged
 
Hi all! I'm new here and I was excatly same issue as many have with that airlock in coolant system (my car Fiat Punto 2004 1.2 8V MK2/2B) after water pump replacement. I tried all methods to get that air off but air still stay hardly stuck in somewhere. Airlock in coolant system was cause even for rough idle and many more issues. Untill I just start trying some desperate method. And amazingly It worked. And it's easy as can be. First You need plastic (or metal pipe) pipe witch one fit inside of filling tank pipe. Maybe You can also use ducktape over pipe avoiding air leaks (see attached picture). In this case I use somekind of part from vacuum cleaner. Next open cap and put Your pipe into tank pipe. Test first there is no air leaks (tiny leak doesn't matter) by blowing gently to pipe. Locate rear bleeding screw and open it little bit so it's easy work with it. Blow Your self made pipe gently and feel the pressure, same time keep opening more bleeding screw. First air coming out with burbling sound. When You can feel only liquid coming out and no burbling sound, start closing screw. Keep the pressure untill screw is closed. Start the engine and 2500-3000rpm, try to hear sloshing sound. If not any sounds, You're done. If sounds sloshing noise, repeat all once again (sometimes tree times). That helped for me.
 

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