COREdevelopments
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| posted on 6/4/08 at 06:45 PM |
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expansion tank or not?
i have got a reno clio expansion tank which i plumbed into my 4age where the heater matrix used to go. however when i raise the engine revs its
pushing water back into the expansion tank. was thinking of re-routing the expansion tank, anyone have any sugestions? or could i just use pressurised
cap on the top rad hose as the original 4age system uses a pressuriesd cap on the radiator. has anyone had any issues with this?
thanks
Rob
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r1_pete
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| posted on 6/4/08 at 06:55 PM |
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The pressure cap should be the highest point on the cooling system, otherwise air pockets will develop at the high points, I'm assuming you tank
cap is the highest point?.
Personally I'd stick with the expansion tank, the level should rise as the engine heats up, as you are pumping coolant through yours a rise with
revs could be expected.
Is it overheating? or any other problems?
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COREdevelopments
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| posted on 6/4/08 at 07:23 PM |
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the engine has just had a full rebuild, so new headgasket, it was rising right to the top with some revs, as revs drop coolant returns to the pipes,
where is the best place to fit the expansion tank main feed pipe? any other 4age builders with some advice on this problem?
cheers pete
rob
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02GF74
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| posted on 6/4/08 at 07:35 PM |
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^^^ my gut tells me that isn't quite right but you do want to have an exapnsion tank or else something will burst or hose will be blown off.
my guess is that you have plumped in the tank to the part of the system where water is being pushed by the pump, the air in the tank, being
compressible, allows level to go up.
plumb the tank to the suction part of the system - there will be (or rather should not be) any air in the sustem for it to be comrpessed so the
convers i.e. water levl in tank dropping should not occur.
do a search as expansion/cooling probs seem to be the bane of builder - unfortunately I cannot find any pictures to confirm what I have wirrten so
treat it with some scepticsim.
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Michael
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| posted on 6/4/08 at 08:03 PM |
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I would advise, re-routing the pipes to the expansion bottle as currently the design you have means the bottle is within the cooling circuit so as
your experiencing when you rev the build up of pressure is pushing the water to the top of your bottle.
I asked on a previous thread how i can plumb my bottle in that i have.
I was advised to have a branch off from the bottom rad hose to the bottom of the coolant bottle and to have the top hose on the bottle going to the
highest point of the engine, so when it expands it will feed back into the bottle.
If you do a search you will find more results i assume.
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Canada EH!
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| posted on 6/4/08 at 09:21 PM |
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expansion tank or not
Usually the expansion tank hose runs off the radiator just below the cap, so when the pressure builds and the gasket on the cap is pushed up the water
flows into the expansion tank. As the pressure and temperature lower the water is then sucked back from the tank to the radiator. In the old days it
just ran onto the ground and you kept filling the rad. The line from the rad needs to go to or near the bottom of the tank, so the liquid can be
sucked back into the rad.
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02GF74
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| posted on 7/4/08 at 07:25 AM |
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quote:
Originally posted by Canada EH!
Usually the expansion tank hose runs off the radiator just below the cap, so when the pressure builds and the gasket on the cap is pushed up the water
flows into the expansion tank. As the pressure and temperature lower the water is then sucked back from the tank to the radiator. In the old days it
just ran onto the ground and you kept filling the rad. The line from the rad needs to go to or near the bottom of the tank, so the liquid can be
sucked back into the rad.
hmm, that is kinda right and wrong.
the early expansion tanks were fed from the radiator neck which had a 2 way valve. when coolant volume expanded, once valve opened allowing coolant
into the tank. when coolant cooled and reduced in volume, a second valve opened that allowed coolant into the radiator. The expansion tank was
ventilated to air and was fitted below radiator neck.
That is how is used to be. On modern cars the exapnsion tank is not plumbed as above but elsewhere and cooling system is sealed. The tank is the
highest point in the system. The radiator does not have the pressure cap but this is now fitted to the exapansion tank. There is no valving to the
expansion tank - the systme is sealed.
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COREdevelopments
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| posted on 7/4/08 at 08:53 AM |
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i have realised that i have plumbed the tank in wrong, will try and plumb it in to the bottom rad hose as the original route i used the tank was
directly in the flow of the coolant, which would explain the rise in coolant.
thanks for the input guys, appreciate it.
rob
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