Coolant leak to raw water on haul out

[JuanPoco]

Hi guys,

I recently hauled out my boat, a few days later I went to replace the coolant/antifreeze. I looked in the radiator cap and to my surprise I couldn't see any. I have checked the level fairly regularly over the last few months at sea and it has been pretty consistent and hasn't required topping up. I pulled the heat exchanger off and there was visible coolant in the raw water intake, water pump">raw water pump, and the raw water intake strainer. Somehow it has leaked back.



Skipperpete said this in another thread which pretty much sums it up.

"A compromised heat exchanger core is unlikely to leak into the exhaust, it will possibly drain the coolant out to sea level via the raw water pump and in some circumstances the coolant tank can refill with raw water, particularly where the engine is below or on the waterline but also from the raw water circuit pressure"


I don't believe the coolant tank was filling with raw water as the level seemed to stay steady.



I have filled the coolant side of the hx with water and there is a small leak showing up in the raw water side but I haven't managed to pin point which tube it is coming from yet. I can see 2 tubes have been previously capped. How do you think I should proceed, take it to a radiator shop and get them to find the leaky tube and cap it?



Thanks again.

[capt jgw]

Originally Posted by JuanPoco

Hi guys,

I recently hauled out my boat, a few days later I went to replace the coolant/antifreeze. I looked in the radiator cap and to my surprise I couldn't see any. I have checked the level fairly regularly over the last few months at sea and it has been pretty consistent and hasn't required topping up. I pulled the heat exchanger off and there was visible coolant in the raw water intake, raw water pump, and the raw water intake strainer. Somehow it has leaked back.



Skipperpete said this in another thread which pretty much sums it up.

"A compromised heat exchanger core is unlikely to leak into the exhaust, it will possibly drain the coolant out to sea level via the raw water pump and in some circumstances the coolant tank can refill with raw water, particularly where the engine is below or on the waterline but also from the raw water circuit pressure"


I don't believe the coolant tank was filling with raw water as the level seemed to stay steady.



I have filled the coolant side of the hx with water and there is a small leak showing up in the raw water side but I haven't managed to pin point which tube it is coming from yet. I can see 2 tubes have been previously capped. How do you think I should proceed, take it to a radiator shop and get them to find the leaky tube and cap it?



Thanks again.

If two have been capped already it seems to be an ongoing problem. You can only cap so many before there's not enough left to do the job. Probably a better idea to replace it.

[rbk]

What engine? Lots of aftermarket options depending on make and model.

[JuanPoco]

It’s an Isuzu c240 (pisces 60hp). Not the most common out there.

[rbk]

Looks like a modified auto engine so basically with a bit of hose you can mount any aftermarket heat exchanger most anywhere you’d like. Seakamp makes a good hx for one option. You should be able to get something new for under $400

[JuanPoco]

That's awesome rbk thanks, from what I had read most people had been saying over $1000 for a new one so I was a little deterred but I should be able to make one of the seakamps work and $400 seems reasonable! I'm in Mexico and the boat will be on the hard for a few months so it isn't a matter of urgency.

[rbk]

Post a picture of your existing hx if you can to confirm. Seakamp is a reputable manufacturer but really any properly sized hx should work as long as it’s not for example integrated into the exhaust manifold like many bowman hx’s where you’re stuck paying a premium price.

[JuanPoco]

Haven't had a good look through seakamps site but will sort it out tomorrow, looks like I should be able to make it work.

[sailah]

I had a brand new cupronickel HX made for my Westerbeke by Lenco in NY this spring. I looked through all the options like Seakamp and some others. But when I called Lenco, they were very helpful on the phone and this is all they do. I ordered at 10am and it was at my door the next day. Price was about the same as you'll find online.

https://www.lencocoolers.com/

They had me confirm all the dimensions and what I got was an exact fit. Very pleased with quality and especially customer service. I am almost positive the guy who answered all my questions was actually the guy who also made it, a rare experience these days.

Mine looks very similar to yours. If you can provide dimensions, they will make it exactly.

[Scubaseas]

If possible get a HX that mounts off the engine. Less vibration and chance of failure to cracking. I got a Lenco about 20 years ago for my Volvo. Still working fine.

[JuanPoco]

Thanks guys, looks like lenco has an exact replica! I will give them a call.