Adding hydronic cabin heat from a AQ140A engine

[Braebyrn]

Let me talk this out here to understand this better.

When the water heats up, it expands. The expansion tank can only allow for a specified amount of expansion. Your saying 6-8%?

If I add the donor heater core and new hose volume, I need to keep it under the 8%?

I'm not sure what to do here, whether I measure the fluid volume that's in the expansion tank, or the entire system without the new donor heater core and hose fluid volumes.

 

[Scott Danforth]

You need to figure out how much extra volume you are adding. Determine what 8% of that is. Then determine if that extra 8% of expansion will cause an issue such as expelling too much coolant.

If your motor utilizes a puke tank, you may need a bigger one.

 

[Braebyrn]

14 feet of 1/2" heater hose = 20 oz.
14 feet of 5/8" heater hose = 28 oz.
donor heater core = 13 oz.
total = 61 oz.
8% of 61 oz = 4.88 oz.