MkIndy7
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| posted on 9/4/07 at 03:58 PM |
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Sealed cooling system?
Althought it shouldn't really cause a problem with the header tank being on about the same level as the radiator.. it is a problem getting the
header tank much higher.
To eliminate these problems and air locks.. would it be possible and beneficial to have a sealed system and an Expansion vessel (bit like a domestic
heating system).
If the system was filled by a hose (or through the higest point which would also have a vent) and the pressure set to just below the pressure of the
rad cap (when upto temperature) then provided you didn't have any leaks anywhere the system should say like that.
The Small expansion vessel could be placed anywhere on the system (was thinking of the heater link on a pinto or by the rad).
Just sounding out an Idea and would value some opinions/problems/feedback etc.
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MkIndy7
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| posted on 9/4/07 at 04:20 PM |
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Were in the process of probably buying a Polo rad...!
There seems no definitive answer as to which is best for the MK.. the Polo or the Micra rad.
The setup you mention is more of a "Expansion Bottle".. I was mening more of a Vessle (Water in the bottom and a cusion of presurised air
above that would keep the system constantly pressurised)
A bit more deluxe and expensive than a factory setup but i'd get the vessel for free from work 
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MkIndy7
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| posted on 9/4/07 at 04:39 PM |
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Yup thats a valid point.. could have a pressure switch in there somewhere that would prevent it from starting if the pressure was low.
If all the gaskets etc were good and new it should hold pressure.. infact it would maybe help as there not constantly heating and cooling and thus
the pressure rising and falling.
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pajsh
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| posted on 9/4/07 at 07:01 PM |
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I could be wrong but AFAIK this is how cars used to be and mine is now.
Aren't expansion tanks just a convenience thing to avoid having to carry around a bottle of water like they did in the old days.
I don't have an expasion tank just a pressure relief cap on the top of the rad and a pipe at the high point to fill up. The pressure relief has
a pipe to drain down to the road if any blows off.
Seems to work fine for me. I just top it up now and then. I admit though for convenience I would like to fit one at a later stage.
I used to be apathetic but now I just don't care.
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MkIndy7
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| posted on 9/4/07 at 07:37 PM |
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The system I'm proposing should in theory never need topping up unless the system pressure got dangerously high and above that of the radiator
cap blow off pressure.
There would be no water coming out of anywhere due to expansion... the water that has expanded would be pushed into the expansion vessel (agains at
air filled bag) and then when its cools down it is forced back out of the vessel and into the system.
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DarrenW
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| posted on 10/4/07 at 09:58 AM |
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My pinto doesnt have header tank. It had a tendancy to blow water out of the cap. Fitted expansion tank (actually a pop bottle at the mo) with pipe
from rad cap into it. Works a treat now. Once it finds its own level it is quite stable.
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MkIndy7
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| posted on 10/4/07 at 04:38 PM |
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Surely the Radiator cap only opens to expel the excess pressure (into the pop bottle)..
What replaces this water when it cools? as the Radiator cap will have re-seated when the pressure dropped as it cooled.
If it expels say 100ml when the rad cap blows off then afterwards the rad system is 100ml short (and still likley to boil up again) or is that not a
problem?.
The only way I could see that setup working is if the rad cap was constantly venting and it "sucked" the water back up from the pop bottle
as it cooled.
I found a small vessel today that needs a minor exterior repair to try the original idea with it.
Any more suggestions or problems anybody can see with the original idea I posted.. or weather its worthwhile at all?
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