Adding hydronic cabin heat from a AQ140A engine

Braebyrn

Cadet
Joined
Jan 27, 2023
Messages
14
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

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
47,304
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

Cadet
Joined
Jan 27, 2023
Messages
14
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.
 

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