Airlocks After Repalcing Coolant/Antifreeze?

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Justin
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Airlocks After Repalcing Coolant/Antifreeze?

Post by Justin » 16 Jul 2009 02:28 pm

Hi, I recall about two years ago replacing the coolant in my 1.4's radiator system and having terrible problems with air pockets after, is it true that this can be avoided by doing it when the car is completely cold and does the interior heat slider need to be set to the hot position before hand, which is what my haynes manual suggests?

j
1988 340 1.4 DL

(I suffer with O.C.D. which makes me obsessed with fine detail)

(Diagrams or photos are far more helpful to me when it comes to cars)

morgan105
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Re: Airlocks After Repalcing Coolant/Antifreeze?

Post by morgan105 » 16 Jul 2009 05:45 pm

The heater slider should be set to hot to allow the water to flow through the heater matrix and back. If this is not open and you are replacing all the water then the matrix will remain empty if set on cold and can cause a air lock when opened. This may eventually clear itself but could take some time. If it goes then you will only need to top up.
This also depends on wether you have a self-bleed or manual type bleed off. If it is manual then there is a small vent screw from the heater, these were mainly on cars before 1982 but after was mainly self-bleeding.

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volvodspec
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Re: Airlocks After Repalcing Coolant/Antifreeze?

Post by volvodspec » 16 Jul 2009 06:16 pm

[quote="Justin"1.4's radiator system and having terrible problems with air pockets afterj[/quote]
do you have a visco or an electric fan?

electric fan equipped models have a self-bleeding coolant system, because of new type radiator (equipped with thermostatic siwtch) and expansion barrel.

is the waterpump working properly and are you sure there are no bloccades in the coolant circuit?

Justin
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Re: Airlocks After Repalcing Coolant/Antifreeze?

Post by Justin » 18 Jul 2009 01:05 pm

Hi, Im not sure what type of fan I have, my car is a Volvo 340DL 1.4 1988 model, it has the fan behind the radiator that comes on occasionally. I dont have a drainage plug so have to do it manually by disconnecting the bottom radiator hose.

Is it best drained when the car is completely cold?
1988 340 1.4 DL

(I suffer with O.C.D. which makes me obsessed with fine detail)

(Diagrams or photos are far more helpful to me when it comes to cars)

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volvodspec
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Re: Airlocks After Repalcing Coolant/Antifreeze?

Post by volvodspec » 18 Jul 2009 01:34 pm

that's the electric fan and so a self bleeding system.

you do have the expansion cap off when bleeding the system (by running engine)?

never heard of a new-type radiator system that had trapped air pockets, on a 343 i've seen it a few times.

pettaw
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Re: Airlocks After Repalcing Coolant/Antifreeze?

Post by pettaw » 19 Jul 2009 05:10 pm

Yeah, all these are 'self-bleeding' but you sometimes need to give them a bit of encouragement. Let the car get cold overnight. Then fill the coolant bottle to max but leave the coolant cap off and set the heater control to max heat. Start the car and let it warm up. Whilst its warming, go inside and put the fan on low to confirm you're getting warm air out of the heater.

Once the car has got towards the halfway mark on the gauge the thermostat for the rad will start to open. Once you start to feel the top hose of the radiator getting hot, go round and carefully give all the radiator hoses a little squeeze to encourage any air to bleed out of the system. Let the fan come on and go off a couple of times and then shut the engine off. Hopefully you'll find that the level in the coolant bottle has dropped a bit. Top back up to max and then cover and allow to cool overnight. You'll probably need to top it again to max the next morning.

Justin
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Re: Airlocks After Repalcing Coolant/Antifreeze?

Post by Justin » 20 Jul 2009 03:10 pm

So basically its best to drain the system when the cars completely cold and make sure the interior heat slider is set to hot?

I suppose when I refill the system its best to do it very slowly?
1988 340 1.4 DL

(I suffer with O.C.D. which makes me obsessed with fine detail)

(Diagrams or photos are far more helpful to me when it comes to cars)

pettaw
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Re: Airlocks After Repalcing Coolant/Antifreeze?

Post by pettaw » 23 Jul 2009 07:39 pm

No, not necessary to do either of those things.You can easily drain when the engine is warm, provided, obviously that its not so hot you burn yourself ;)

Don't have to be careful to fill slowly, just fill carefully until its full.

Only thing that's important is to fill and drain with the heater control on full heat.

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