383backinblack

I'm a little stumped with this one.......I have a big 4-core radiator, a powerful electric pump and NO thermostat........the car normally runs between 150-180 depending on the temp outside.......

the car has a radiator cap, with the overflow plugged.....and a water neck on the intake with a radiator cap and the overflow going to a moroso aluminum recirculating overflow tank.......so while driving the car at 180ish degrees......after you stop....coolant will **** out of the air hole on top of the overflow.....it seems to do it occasionally while driving as well. but I repeat the car is NOT hot at all.....its not boiling.....

so what gives? is it the cap being overpowered by the water pump? if you turn the pump on without the cap on top of the intake water comes out about 18" high.........or is it something with the way its plumbed? or perhaps the tank is just too small for the amount of expansion the system has? I'm out of ideas, because even after the radiator gets pretty low on coolant it still does it.

some fresh ideas would be great

safemode

iTrader: (1)

i think it's pretty obvious the electric water pump is too strong for your setup

btw, why did you go with an electric water pump? Dont they only last a couple years if you take your car out often?

383backinblack

I'm really not sure.....cause I never had the problem before when the overflow was coming off of the radiator. maybe i'll try putting it back there and plugging the waterneck overflow. I've had an electric waterpump for a long time and i've never had a problem with the 2 i've owned (moroso and summit).

safemode

iTrader: (1)

if the overflow is between the water pump and the radiator, then you'll have a high pressure and low resistance situation. So when the water pump stops pumping at a high rate, the water is "pressurized" and wants to go to the direction of least resistance. Putting the resevoir after the radiator (like stock), puts the overflow after the section of higher pressure (since the radiator is seen as an obstruction in water flow).

In any case, you'd want the resevoir to be sapping it's fluid from the highest position in the coolant system. Having the resevoir at any lower position than the highest makes it a better direction to flow into than the alternative, which is bad.

383backinblack

well thats the problem is where it is now is the highest point in the system.....moving it to the radiator cap will make it lower

safemode

iTrader: (1)

well being at the highest point isn't good if it's also a high pressure area that causes fluid to gush out of it Your best bet is after the radiator. One of the other main reasons they put the overflow at the top of the radiator rather than somewhere closer to the engine block (technically higher up) is because the top of the radiator is where you trap most of the air that accumulates in the system.

another thing to consider is how big of a connection your resevoir has with the coolant system. It should be about as big as the stock tube is. This further helps restrict the coolant from wanting to go up the resevoir tank rather than back around the coolant system.

mesterz2889

wouldn't a thermostat help to keep the pressure of the cap at least some of the time?

383backinblack

ya thats a good point, as thats where it goes stock.....and its definitely not the highest point in the stock system either......I'll hook it up that way and see how it works tomorrow morning. that bites though, no more 1/4" nylon push-lock tubing for that haha that was a nice piece

383backinblack

ok.....swapped the coolant overflow back off of the water neck and onto the one on the radiator cap at the radiator......and so far it seems to be working as it should......i'll know more tomorrow when i go out to the garage and see if it pissed anything out or if it sucked the coolant in the tank back in like its supposed to.....but so far it seems like that fixed it.....

thanks for the input people