Cummins Marine Diesel Repower Specialists Forums Cummins Marine Engines White smoke from dipstick and oil cap

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  • #33272

    Baldassare Gerardi
    Participant
    Vessel Name: 35 Open
    Engines: Cummins 6bta 370hp
    Location: NY
    Country: USA

    I have an idea but appreciate all input & advice. My Cummins 370hp 6bta 1k hrs #45916445 Stbd motor has a light puffing white smoke from dipstick and oil fill cap. It’s light on startup and increases as the engine heats up with idle. I noticed antifreeze loss from from reservoir at the end of last season (approx 1/3 gallon per50hrs). I have not done an oil analysis due to a fresh oil change (proper level). I do not have any white smoke or oil slick from my exhaust. Engine has normal Blowby and no change in startup and performance. In the beginning of last season the engine did briefly overheat from a clogged intake while underway, but was immediately shut down and corrected. My thought is a coolant leak at the head gasket or head area. Any thoughts or recommendations on a head gasket repair stop leak coolant addative? Possibly re-torque the head bolts (specs)? Replace head gasket $$$? Or are there any other potential areas (turbo or aftercooler leak)that could cause this light oderless haze?

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  • #34067

    Baldassare Gerardi
    Participant
    Vessel Name: 35 Open
    Engines: Cummins 6bta 370hp
    Location: NY
    Country: USA

    I know the aftercoolers need servicing this offseason. The boat is propped well WOT 3000 @ 30kts loaded up. Tachs unverified but speed is.
    Overheated middle of last season from clogged intake while cruising and immediately shut it down then alarms sounded. Noticed antifreeze loss from reservoir in the beginning of the season which caused me to pay attention to now white smoke from Blowby tube and dipstick/oil cap.

    #34062

    Rob Schepis
    Forum Moderator
    Vessel Name: Tenacious
    Engines: 6BTA 5.9 330's - "Seaboard Style"
    Location: Long Island, NY
    Country: USA

    Good pics. That starboard aftercooler is a tad cooked. How is this boat propped? Does she hit 3100-3150 WOT easy when she’s all loaded up as you use her? Tachs verified?

    How about the overheat? How was it discovered? What did you discover upon inspecting the engine when you shut it down? If you didn’t dump the coolant sometimes it beneficial to let her idle and keep the coolant flowing.

    #34051

    Baldassare Gerardi
    Participant
    Vessel Name: 35 Open
    Engines: Cummins 6bta 370hp
    Location: NY
    Country: USA

    Hi Tony thanks for reading. I’m saying my Blowby is ok by comparison to the port motor using a dollar bill and not noticing any difference between the two. This is my third season with the boat and I plan on overhauling the aftercoolers as per your protocol at the end this season. I attached some pics of the install. I’ve read in other posts that you’ve on occasion recommended alumaseal for antifreeze leaks and was wondering what your opinion was on using it for the head gasket or another product that’s geared more for the gasket material. Also if I do use a stop leak product, would it be a waste to replace the head gasket in the off season if the condition is corrected. I appreciate any suggestions or recommendations thanks.

    #33516

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

    Let’s start with this: I want to see really good pics of your installation from all angles & perspectives-I especially want good pics of you exhaust system, and aftercooler & turbo……………..How do you know what your blow-by numbers are?

    Last time your aftercooler(s) was put on the bench and serviced per my protocol?

    1000 hrs and having issue requires “new eyes” & thoughts about what is going on in your engine room.

    Tony

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