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Heat Exchanger Gaskets

Discussion in 'Ocean Yacht' started by Boomer, Dec 26, 2019.

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  1. Boomer

    Boomer Senior Member

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    Getting ready to pull the heat exchangers and oil coolers to get them all cleaned out and ready to go for the new season. I have 1983 671 TI Johnson Tower diesels....I have looked thru my manual and not see any listing for gasket numbers or torque numbers for the bolts...does anyone have a company to get the gaskets from and know the torque setting for the bolts?
  2. rtrafford

    rtrafford Senior Member

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  3. PacBlue

    PacBlue Senior Member

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  4. Capt Ralph

    Capt Ralph Senior Member

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    Does it look like this?

    Attached Files:

    • HE.pdf
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  5. Boomer

    Boomer Senior Member

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    Yes sir! That's the water side...was going to do the oil coolers also
  6. Capt J

    Capt J Senior Member

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    Any D.D. dealer should have them.
  7. Boomer

    Boomer Senior Member

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    Wasnt sure as Johnson Towers was involved
  8. Capt Ralph

    Capt Ralph Senior Member

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    The source data is pretty old (BD). Part numbers may been superseded a few times (as usual).
    As Skippy J posted; A better DD shop should be able to help with your serial number.
    PM me your direct e mail again and I'll load you up on what I have.
    Is your oil cooler on the bottom of the H/E as pictured?
    Here is what I think on this; it is coolant cooled and not leaking::: don't f*** with it. Don't open Pandoras box. You only want to clean the green water sides of things.
    If nothing is leaking, why crack anything apart? Have we already talked about chemical cleaning and checking dump cans?
    Last edited: Dec 26, 2019
  9. Boomer

    Boomer Senior Member

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    Done...thanks bossman!
  10. Capt Ralph

    Capt Ralph Senior Member

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    OE working now. Saved as Boomer.
    BTW, old sub mariner?
  11. Boomer

    Boomer Senior Member

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    Nah... name of the Post 46 we missed out on when first shopping for boats...lol
  12. Boomer

    Boomer Senior Member

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    ...dump can is clean. Tried barnacle buster poured in 2x from the raw water exhaust tube...I will skip the oil cooler under the h/e and the one by the fuel filter and only do the h/e shown...think I should do the thermostat also? No idea when it was last replaced?
  13. Capt Ralph

    Capt Ralph Senior Member

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    I'm getting my 671 guys confused.
    I thought you already replaced the thermostat.
    It's on the coolant side and it usually works or does not.
    I recall the JT stat was custom and expensive.
    If not you, then do a search on YF for 671 stat part number and change out.

    There is an open / close profile these fancy stats offer. Meant to get the engine hot faster, longer and late to cool down. The idea is; cold or cool engines can not burn fuel completely if not up to temperature.

    But IMO, it's close (a hair under) to hot. No margin for error. If possible, stay with matching factory (DDC) stats in both engines.
  14. Boomer

    Boomer Senior Member

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    Well, pulled her all apart...HE were not bad on the raw water side but the coolant side had a lot of crap in it...lots of mud in the HE tank also...zincs were almost gone after a season also...waiting on parts from johnson towers including new t-stats
  15. Capt Ralph

    Capt Ralph Senior Member

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    Mud? brown/red mud? Long dead coolant and possibly a sea water leak.
    How did the big HE O rings look? Any other signs of coolant contamination?

    Do me a flavor, put all back together and just ad tap water to the coolant side, no sea water.
    Air charge the coolant side to no more than 8 psi and walk away for a day or two.
    If you loose pressure, check all out before your final reassemble and ad coolant.
    You may have a bad solder joint in the DDC HE.
  16. Boomer

    Boomer Senior Member

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    Dark brown mud...more on the motor that was getting hot than the other side...oddly, there was no big o ring on the overheating motor except the one in the flange...the one that butts up against the flange was not there like on the other motor...both HE will be pressure tested at the radiator shop for leaks...i was always losing a (very) little antifreeze on the motor without a gasket...i will fill with water and pressure test as recommendedQUOTE="Capt Ralph, post: 284511, member: 921"]Mud? brown/red mud? Long dead coolant and possibly a sea water leak.
    How did the big HE O rings look? Any other signs of coolant contamination?

    Do me a flavor, put all back together and just ad tap water to the coolant side, no sea water.
    Air charge the coolant side to no more than 8 psi and walk away for a day or two.
    If you loose pressure, check all out before your final reassemble and ad coolant.
    You may have a bad solder joint in the DDC HE.[/QUOTE]
  17. Boomer

    Boomer Senior Member

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    Should I have a 7 or 15 psi radiator cap?
  18. Capt J

    Capt J Senior Member

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    I was running a set of low hour (SMOH) 6-53's TI's and one would run hot if pushed past 1600 rpms (1600 rpms was hull speed on this particular displacement hulled boat). We pulled the heat exchanger and the salt water side was very clean, the coolant side was full/packed with sediment and goo.
  19. cleanslate

    cleanslate Senior Member

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    Ka - Boomer ! Happy New Year and also to all...
    I just got done mine. I did both myself. I also had old rusty mud in mine, I just wiped it out etc ... Mine have not been done for years, I guess by the looks of it 10 plus years or so.
    Got my gaskets from J and T in New Jersey , mine 471 ti J and Ts ..
    Don't worry about the rusty mud, it's a normal thing with our old , past owners poorly serviced Detroits.

    Just make sure you take your time with it all. Don't break anything, as all of the stuff is no longer made! The tank and heat exchanger etc...
    Make sure you take the time to remove all the old gasket matrial , by hand with a fresh 3/4" wood chisel . Presoak the old gasket with PB blaster to help with removal. It's got to be completely clean for a good seal.. It's two big o-rings And a round metal spacer between the o - rings .

    Fit everything loose , on both ends to help the exchanger and gaskets seat right. Then snug Down the discharge side first , with the intake side all bolts very loose. The snug down the intake side . I put in all new bolts and lock washers to by the way. Just hardened steel ones from the hardware store. They don't need to be cranked down hard. Just a good snug tightening .
    Last edited: Jan 3, 2020
  20. cleanslate

    cleanslate Senior Member

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    Of course, my reply above was before I looked at CR diagram ...
    Anyway , Boomer ! Yours is bigger than mine ! Lol
    My 471 tank is a little less sophisticated. My oil cooler is on the bottom of the tank , laying flat on the bottom. And I have less "stuff" going to the tank.

    Hum , Captn Ralph ...not sure if or where my thermostats would be...I know if I've got them , they are old.
    And why do they need them ? Just to help the engine warm up faster? Or regulate the temp while under way ?