Cummins Marine Diesel Repower Specialists › Forums › Cummins Marine Engines › 1987 210hp 6BT temperature issue

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  • May 9, 2019 at 1:46 pm #69142

    Mike
    Participant
    Engines: 6BT
    Country: United States

    engine running 180 degrees at idle. Normal idle temp is 155-160. changed impeller and flushed ENTIRE raw water system. back flush through water inlet in hull also. No debris in transmission cooler. Still same as before.
    1) can the wear plate or cam on impeller housing cause this?
    2) If its not on raw water side, and I’m not loosing any fresh coolant, what is the next to look for?
    3) I have a 180 degree t-stat in there and have for ever.
    Thanks Mike

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Viewing 11 replies - 1 through 11 (of 11 total)
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  • July 1, 2019 at 7:57 pm #74558

    Bill Stenger
    Participant
    Engines: 250 Hp 6bt M1
    Country: United States

    That’s great news. I dropped my exchanger off today to be clean and serviced. I didn’t think to
    drop off the tank as well good idea. Mine is
    an absolute mess.

    July 1, 2019 at 10:49 am #74522

    Mike
    Participant
    Engines: 6BT
    Country: United States

    problem resolved

    Bill, after removing and rodding out the heat exchanger, and installing the new 160 T-stat, the issue seems to be resolved
    Its running at about 176-178 degrees on cruis at 2100 RPM and cools down to about 160 when I back down to idle speeds.
    I believe the exchanger has a lot of “scum” built up because when I filled it with a 50-50 mix of acid and water, it changed the tube co;or from grayish to copper and I did this 2 times for about 20 minutes each time.
    I also had the expansion tank repaired at a local radiator shop, who boiled it overnite in acid and then soldered or welded up the bad areas, and it pressure tested to 20 lbs.
    I have 2 offshore trips in the last 3 weeks (30 miles each way) and it preformed great. Although it did loose about 2 quarts of coolant after the 1st trip, may have been low on the initial fill, not sure as I just returned Saturday and have yet to check my fluid levels

    June 28, 2019 at 11:43 pm #74456

    Bill Stenger
    Participant
    Engines: 250 Hp 6bt M1
    Country: United States

    Any result on this I have a similar issue? My coolant temp will go up to 195 @ wot and 190 @ 2300 cruise.

    May 15, 2019 at 5:30 pm #69497

    Stephen Oliver
    Participant
    Vessel Name: Ascella
    Engines: 2x Cummins 330hp Diamond
    Location: Perth, Australia
    Country: Australia

    That’s ok then!

    Wouldn’t want you to have taken the engine apart for a dodgy connection… Ask me how I know !!!!

    Steve

    May 15, 2019 at 2:21 pm #69475

    Mike
    Participant
    Engines: 6BT
    Country: United States

    Stephen Oliver

    Yes sir I shot temps with IR temp gun and it matched my gauge

    May 14, 2019 at 10:51 pm #69438

    Stephen Oliver
    Participant
    Vessel Name: Ascella
    Engines: 2x Cummins 330hp Diamond
    Location: Perth, Australia
    Country: Australia

    Have you actually shot the engine with a laser temp gun? I ask as I spent a while chasing an overheat, but gun said not.. took the gauge cluster off and had a fiddle and lost 5 deg C I’m sure if I clean the contacts I’ll lose another 5 deg.. and it will match the SB engine. Check and clean and grease all connections to the gauge to see if it makes a difference!

    Steve

    May 14, 2019 at 9:20 pm #69436

    Mike
    Participant
    Engines: 6BT
    Country: United States

    keep on digging

    today I pulled the heat exchanger and flushed it with a 50/50 mix of water and muratic acid.
    salt side brightend up the copper tubes and
    I got a little grey-ish washout
    about a 10 minute soak
    freshwater side I capped one end and gave it a 5 minute soak of same 50 50 and rodded it out after soak
    able to reach all rod tubes except outside diameter tube access blocked by housing. then flushed with fresh water. washed out with a blackish residue but flushed out clean. then flushed the block with fresh water. the Tstat and housing are off flush out was clean,
    Boiled tstat and it opened at 180 degrees, there was some saltish or calcium ish buildup on the stat shaft
    Awaiting my 160 degree tstats should be here in the next few days
    So All is flushed out and ready to re-assemble
    Is the water pump an issue here

    note the heat exchager gged them up from dissolving.

    May 14, 2019 at 5:11 am #69392

    Mike
    Participant
    Engines: 6BT
    Country: United States

    tonys advise please

    Tony
    I know your a busy man,
    but,I did reply to your questions above on the temperatures at speed.
    Thanks again Mike in Texas

    May 13, 2019 at 6:09 am #69327

    Mike
    Participant
    Engines: 6BT
    Country: United States

    temps

    Tony, cruise at 2050 rpm im reading 190 If I stay on it for over 20 minutes it stars to creep up to 195 so I have to lower my RPMs down to 1900 to be comfortable in the 185 range. when I back it down to idle it comes down to 180
    I did order your 160 degree tstats over the weekend hoping for lower running speed temp.
    IR gun confirms these temps
    Thanks Mike

    May 12, 2019 at 6:38 pm #69311

    Tony Athens
    Moderator
    Vessel Name: Local Banks
    Engines: QSB 6.7 550 HP
    Location: Oxnard, CA
    Country: USA

    ????????????????

    Idle temps are of not concern to me.. In fact, If someone could come up with a reverse thermostat for a B that would let the engine idle at 180-190F but then drop down to 160-170F at cruise. that would be good from my perspective..

    So, what is your temp at CRUISE thru WOT?

    Tony

    May 11, 2019 at 6:47 am #69239

    Mike
    Participant
    Engines: 6BT
    Country: United States

    any one have some info in this? I will break down the heat exchanger if needed, just want to eliminate any other possibility first

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