Radiator Level Question

[Shep69 149]

Im just wondering if its normal that my radiator fluid level is always low . I decided to purchased a new 13 pound cap just to see but when the motor starts  to reach running temp around 170-180 it starts venting fluid . The motor runs fine and never overheats . If I go to top the radiator up it takes about 1 litre or so. Motor is a 351W with the larger A/C radiator . Currently running a type "B" non glycol based coolant. Anyone have any ideas. 

[JET 445 43]

I put a recovery cap on mine with an overflow tank, never have to worry about it again.

[BuckeyeDemon 211]

I add water so it just covers the cores which is the area of the radiator that should be transferring the heat out.  that basically gives the whole top tank area room for expansion.  

[barnett468 418]

How far below the inner rad cap sealing surface are you filling it to?

[Shep69 149]

4 hours ago, barnett468 said:

How far below the inner rad cap sealing surface are you filling it to?

About 1/4 below Barnett. It ends up venting out so it about 1/2 inch above the cores. Maybe this is normal as BuckeyeDemon says. 

[barnett468 418]

1 hour ago, Shep69 said:

About 1/4 below Barnett. It ends up venting out so it about 1/2 inch above the cores. Maybe this is normal as BuckeyeDemon says. 

yes, it is normal, plus, i always use 13lb caps. one that is much less will easily allow water to escape. i would put the level around 3/4" below the lowest part of the neck providing it is still above the tubes at least 1/4".