expansion tank question

[rick]

Hi, I am going to put an electric waterpump up front, what if I connect the expansion tank after the water pump before it enters the engne block (still cold water) as this save's me a water hose from the front of the car(before the pump) to the rear (where I have the ecpansion tank)

or do I need to put the electric water pump in the back,

thanks, rick

 

[Bill Musarra]

Off the top of my head, there needs to be two expansion areas. One where you add water to the system, and that is linked to an overflow container(not pressurized), for the expanding water or vent for any trapped air. So the purpose or the tank is two fold. One is to catch any air that may have become trapped in the engine before it can get to the radiator and then pump. A big air pocket in the radiator will decrease the cooling effect and could lead to overheating I would think. If it made it to the pump it could form a vapor lock situation. The second is that it is an area for the water to expand(read hot), and if under pressure can flow out to the secondary overflow pot or container to later be sucked back in as it cools, or after shutdown. So it would have to be right after it leaves the engine. Here is how I plumbed mine.

The pump needs to be in the front in my opinion. It needs to see only cool water, and pumps toward the engine. Anybody got a different idea??

Bill

 

[rick]

Thanks Bill, I have however just one (bigger) expansion tank (the setup is like the lotus esprit) and seems to work ok it is just that I want to go the remote electric route and reed a lot on this site about the connection of the expantion tank in relation to pressure in the system

rick