consequenses of no expansion bottle? alternative

[leefitz]

hey, i may need to remove the expansion bolle from my car and if i do, what is the down side of this? is there an alternitave to this?
 cheers lads

[AtomicRex]

If you want a neat little tank we make this
 

 
£40+VAT(£48)

[HaywardRotary]

The engine should allway\'s run an expansion tank all the time as the coolant has to expand when it gets hot and needs somewhere to go,then when the engine cools down it draws the coolant back into the engine to keep it topped up with no air entering the system.
Regards
Carl

[leefitz]

Cheers men,  what volume of expansion would be expected from a system? I understand that it would be greater in a system with a larger radiator but I don\'t really have a gauge on the increase. Cheers

[SiH]

If you want a neat little tank we make this
 

 
£40+VAT(£48)

I\'m guessing that\'s upside down? Is there a vent on the other end? Otherwise how does the pressure equalise? And how do you fill it?

[leefitz]

I\'d guess your right, that or the pipe runs nearly to the bottom of the bottle and there\'s a hole on the other side of the pipe that you can\'t see.

[AtomicRex]

The pipe in here runs straight to the bottom of the tank.
 
This is assuming you have a neck on the top of the water pump with an overflow nozzle.  On the engine pressuring up, when it reaches the pressure stipulated by the cap, it will throw excess water down the pipe into the catch tank.  When the engine then cools...it produces a vacuum  this in turn opens the cap and pulls the water back from the tank.

[SiH]

So you\'re talking about using an FC filler neck? And eliminating the AST, yeah?

I\'m probably missing something, but I can\'t see that tank working - you\'re basically turning the cooling system into a \'closed\' system like many european cars run - you\'re sealing a finite amount of air in the system - when the coolant caps opens as it hits it\'s crack pressure, it will overflow either air or coolant from the rad into the tank - however, the more that goes in, the greater the pressure, and the rad won\'t fully breathe, surely? You need to release the pressure in the overflow tank, surely? Otherwise the pressure building up in there will fight the pressure in the cooling system.

If you don\'t allow the tank to be topped up with water like an OEM one, you run the risk of, (in circumstances where the cooling system contains air that is then pushed out through the rad cap before coolant, i.e. when it\'s just been refilled) running out of \'reserve\' coolant to pull back in as the system cools.

If you manage to fill it to a st level and then conenct it up, then you don\'t get the issue, but as it pulls liquid out, the air pressure in the air gap will drop, and fight the cap pressure won\'t it :confused: