RentonRiggos
Member
I had my heat exchangers pulled this year for a pressure check. There had been some increased coolant usage on one engine over the other on end of year cruise in 2020.
When tested, one HX was fine and one had a hole in a tube (1 of 15 tubes). I was presented with options to have a new HX fabricated (engines are DD 8.2T's and parts not easy to find) or to have the offending tube plugged. The new fabrication cost was 4.5X the repair.
Plugging the tube will leave me with 14/15 tubes (a loss of 6.7% heat transfer efficiency?). I am deciding to do the repair based on the following assumptions... 1) The HX could have been designed without some factor of safety for heat transfer efficiency. 2) I boat exclusively in the PNW and the raw water is much colder than in other climates (probably 20-30 degF delta T from FL?) that I assume they need to design boat systems to be able to handle.
Am I way off base with my thinking or should this be fine as long as I keep an eye on the running temperatures?
When tested, one HX was fine and one had a hole in a tube (1 of 15 tubes). I was presented with options to have a new HX fabricated (engines are DD 8.2T's and parts not easy to find) or to have the offending tube plugged. The new fabrication cost was 4.5X the repair.
Plugging the tube will leave me with 14/15 tubes (a loss of 6.7% heat transfer efficiency?). I am deciding to do the repair based on the following assumptions... 1) The HX could have been designed without some factor of safety for heat transfer efficiency. 2) I boat exclusively in the PNW and the raw water is much colder than in other climates (probably 20-30 degF delta T from FL?) that I assume they need to design boat systems to be able to handle.
Am I way off base with my thinking or should this be fine as long as I keep an eye on the running temperatures?