Coolant Leak

Apr 17, 2013
153
Catalina 310 57 Pompano Beach, FL
Have been doing multiple jobs on the boat. Disconnected the discharge hose from the raw water pump to the heat exchanger to work on the alternator. I have been losing coolant in the overflow reservoir. When I went to connect the hose back to the water pump noticed that coolant was in the hose. This hose connects to the bottom of the heat exchanger. Before I buy a new heat exchanger does anyone know of another situation which could cause this issue. Recently had the heat exchanger boiled out 150 hrs ago.

Thanks,
Mark & Joy
S/V Sweet Pea
 
Apr 17, 2013
153
Catalina 310 57 Pompano Beach, FL
Thinking that there is a hole in the heat exchanger which is allowing the coolant to leak in to raw water side.
 
Jan 22, 2008
214
Catalina 310 #147 Oakville Yacht Squadron
Thinking that there is a hole in the heat exchanger which is allowing the coolant to leak in to raw water side.
Yep
Maybe the boiling out was overzealous; but the HX is subject to brutal vibration because of how much our engines shake at idle
 

rukidn

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Apr 23, 2012
160
Catalina 310 258 Sandusky, OH
A local radiator shop may be able to test and repair if the leak is at the end of a tube. It is also quite acceptable to have them block the ends of one leaking tube, which would not compromise the effectiveness much. I had my HX repaired over the winter for about $60 and working fine.
 
May 10, 2012
14
Catalina 310 Bayport
I recognize this is a dated response, but I replaced the HX on hull 26 this spring 2016 after finding coolant in the bilge and tracing the leak back to the HX. Was able to replace it myself with the aid of these "great" forums. As noted in many of these forums, the M25XPB engine Idle / vibration is brutal on the HX ( need to ensure you're idling around 1,000 rpm.....anything lower and you get vibration issues ). Upon removal of the old HX found one of the old brackets had broken away from the HX and caused a small hole. Found a new HX on line for U$450 vs C$1,200 in Cda......was C$800 after fx, delivery and customs........delivered in 3 days.......took the old one in ( on the advise of these forums ) to a local radiator shop.....pressure tested and fixed for $80 the same day. Hassle of returning new one not worth the aggravation......now have a spare. Recommendation would be to remove your old hx and take it to a radiator shop for refurbishing if you are having issues......buy the new brackets to reinstall it, or get someone to fabricate new brackets for $25-$50. I likely saved $2,000 doing the installation myself after the frustration of paying an exorbitant $1,600 for a new sherwood water pump installation.....I know, I know it's not an Obeberdorfer......much harder to get many of these products in Canada! New HX works like a charm running at 160°F......will ďo an Oberdorfer if the Sherwood fails while I still own the boat. Much appreciate the great insight gleaned from these forums.....wouldn't have attempted the HX project without the information provided here.
 

Tom J

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Sep 30, 2008
2,301
Catalina 310 Quincy, MA
According to the manual, idle on our engines should be around 1,250 RPM. This yields much less vibration and does no harm to the transmission. I had tried less than 1,000 RPM, and broke my first set of brackets for the HX. Now on my third set of brackets (1,500 hours), and new brackets are much heavier, but place the HX right over the tranny dipstick. Now I will need to pry the HX over a bit when I go to change the tranny oil.