Click for Cross Click for Lurssen Click for Llebroc Click for Westport List Your Boat

Overheating Issue

Discussion in 'Ocean Yacht' started by Boomer, Jun 2, 2018.

You need to be registered and signed in to view this content.
  1. cpthawk

    cpthawk New Member

    Joined:
    Apr 1, 2019
    Messages:
    12
    Location:
    Tarpon Springs
    Boomer
    Replied to your Flex Flier thread.
    Cheers Capt Joe
  2. Boomer

    Boomer Senior Member

    Joined:
    Oct 14, 2017
    Messages:
    671
    Location:
    Seminole
    Received and thank you
  3. cpthawk

    cpthawk New Member

    Joined:
    Apr 1, 2019
    Messages:
    12
    Location:
    Tarpon Springs
    If your interested in the J&T boost coolers contact Ron. I think he still knows where to get them. Solved all the summertime cooling issues on our boat.
  4. Boomer

    Boomer Senior Member

    Joined:
    Oct 14, 2017
    Messages:
    671
    Location:
    Seminole
    Good morning all...my dreaded overheating issues have resurfaced while at speed...long slow creep for a mile or 2 before I have to pull them back to cool down....I have new raw water hoses, new impeller, heat exchangers boiled out this spring, trans cooler just descaled with barnacle buster, new coolant pump in one motor, coolant good and clean, new t stats, no bubbles in overflow tanks. What am missing? I even dove under the boat with a putty knife to make sure the intake screens were clear
    Last edited: Jul 12, 2020
  5. Boomer

    Boomer Senior Member

    Joined:
    Oct 14, 2017
    Messages:
    671
    Location:
    Seminole
    I lost the info for the boost coolers...i am overheating again with these warm gulf temps
  6. chesapeake46

    chesapeake46 Senior Member

    Joined:
    Jul 26, 2009
    Messages:
    1,631
    Location:
    Chesapeake Bay, Delaware Bay & S.Jersey
    Do you have cast iron heat exchangers for the engines ?
  7. Boomer

    Boomer Senior Member

    Joined:
    Oct 14, 2017
    Messages:
    671
    Location:
    Seminole
    The tank is cast... the h/e are brass or.something like that
  8. chesapeake46

    chesapeake46 Senior Member

    Joined:
    Jul 26, 2009
    Messages:
    1,631
    Location:
    Chesapeake Bay, Delaware Bay & S.Jersey
    We do not have the temps you do there but the river water does get warm, ( it;s 85* today ).
    I used to have your problem in August when river & bay temps rose & the Rock Fish dove deep for cool water.
    I was assured by J&T and others that my cast iron heat exchangers were fine for my engines. ( only 410 hp 6-71's )
    However:
    My HE's were used in a broad range of horse powers and in the laboratory, they work great.
    In real life over time things are not in laboratory shape.
    I changed my heat exchangers to Lencos in 2007 and have had zero trouble with overheating since
    The lencos will probably not last as long as the cast iron units, this is true but I am ok with that.

    I only put about 100 hrs a year on mine. for reference.
    (No relationship w/ lenco btw.)

    I used to clean out my system with Muriatic Acid when the temps began to climb but had a bad experience with that which helped convince me to loose the cast iron HEs
  9. Capt J

    Capt J Senior Member

    Joined:
    Jul 11, 2005
    Messages:
    13,978
    Location:
    Fort Lauderdale
    What about your fuel coolers? Is there any place the engines could be sucking a little air? Cracked raw water intake hoses, sea strainer lid gaskets, etc? Is a diver doing a really good job at cleaning your raw water intake screens on the bottom of the boat? What about behind them? Basically I would start at the intakes and follow everything in the path of the raw water.
  10. Boomer

    Boomer Senior Member

    Joined:
    Oct 14, 2017
    Messages:
    671
    Location:
    Seminole
    New raw water hoses this year, heat exchangers boiled out in spring, new impeller, oil cooler above shaft acid cleaned with barnacle buster, new circulation pump on one motor...I even use a dab of rtv when fitting the hoses to the hard parts in case I was ducking some air somewhere
  11. Boomer

    Boomer Senior Member

    Joined:
    Oct 14, 2017
    Messages:
    671
    Location:
    Seminole
    How do you get behind the screens? No sea strainer tank btw
  12. Capt J

    Capt J Senior Member

    Joined:
    Jul 11, 2005
    Messages:
    13,978
    Location:
    Fort Lauderdale
    They slide out, you need to be under the boat and a diver.
  13. Capt Ralph

    Capt Ralph Senior Member

    Joined:
    Sep 8, 2004
    Messages:
    10,055
    Location:
    Satsuma, FL
    New hoses from the thru hull all the way up?
    Dump cans cleaned?
  14. Boomer

    Boomer Senior Member

    Joined:
    Oct 14, 2017
    Messages:
    671
    Location:
    Seminole
    Roger...dont thinks screens have been pulled by a diver
  15. Boomer

    Boomer Senior Member

    Joined:
    Oct 14, 2017
    Messages:
    671
    Location:
    Seminole
    New raw hoses sir as you directed last time...I will endoscope the dump cans this week...
  16. Boomer

    Boomer Senior Member

    Joined:
    Oct 14, 2017
    Messages:
    671
    Location:
    Seminole
    Someone mentioned thinning the 50/50 coolant to 70/30 with purified water? Thoughts?
  17. Boomer

    Boomer Senior Member

    Joined:
    Oct 14, 2017
    Messages:
    671
    Location:
    Seminole
    Boat was fine a few weeks ago when gulf was mid 80s...now that it hit 90, same issue as last summer
  18. Capt Ralph

    Capt Ralph Senior Member

    Joined:
    Sep 8, 2004
    Messages:
    10,055
    Location:
    Satsuma, FL
    I usually go the 60/40 or less but this is not your issue.
  19. chesapeake46

    chesapeake46 Senior Member

    Joined:
    Jul 26, 2009
    Messages:
    1,631
    Location:
    Chesapeake Bay, Delaware Bay & S.Jersey
    Before I replaced my cast iron HE, I tried distilled water and Nalcool which is supposed to dissipate heat better than anti freeze.

    It did not help my situation.

    Had to replace the antifreeze in the fall here of course.
  20. cpthawk

    cpthawk New Member

    Joined:
    Apr 1, 2019
    Messages:
    12
    Location:
    Tarpon Springs
    i believe these boost coolers were made for J&T by sen-sure marine in Lauderdale. these were installed on the boat in 2000, no more heating issues. they replace that cross feed pipe that's been discontinued.
    boosttop.jpeg boost2.jpeg