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  1. #1

    Default Oil coming out valve cover hose

    I have oil coming out my valve cover hose on a KAD43 Took it to a mechanic, they said I have excess crankcase pressure. Tested the compression and said it was fine. They then turned to the turbo, said it was the culprit and replaced it. With the new turbo I still have the same issue.

    I've been told by one mechanic that didn't have the time to look at it that I should put a bigger breather hose on as this is a problem with these engines. I've also heard it could be stuck rings.

    Any ideas or solutions before I have to go pay another mechanic?

  2. #2
    Join Date
    Dec 2006
    Palm Beach, FL, USA

    Default Re: Oil coming out valve cover hose

    Never go back to the mechanic that suggested turbo, and made you pay for new one......please. Yes, turbo makes pressure, but not in the crankcase.

    Excess crankcase pressure comes from combustion chamber. Also known more commonly as "blowby". Stuck/cracked ring(s), or worn out cylinder sleeves, or cracked piston crown(s). Easy way to check for blowby is take oil filler cap off, place your hand over opening while engine is running, and see if you feel pressure pushing on your hand.

  3. #3
    Join Date
    Aug 2006
    Toronto, Ont, Canada

    Default Re: Oil coming out valve cover hose

    Start with checking your oil level... next I would examine the drainage from the rocker area. There is a small feeed pipe with a o ring on both ends... if one has slipped worn or broke then the front rockers will be starved and the rear will be swimming in oil. I found one engine missing this part and the other with the wrong size o ring installed.
    After fixing made a BIG difference. Let us know what you find as this is a common complaint (oil from breather) on many large diesels and most mechanics want to blame the compression or valves without considering drainage issues first.

  4. #4

    Default Re: Oil coming out valve cover hose

    The mechanic did the oil fill cap test and said nothing seemed off. I will try looking at the rockers and see if something is wrong there.

    Is it possible for some carbon buildup in the engine to cause these issues? My next plan is to change the oil and filter as well as the breather valve hose and see if that helps.

  5. #5

    Default Re: Oil coming out valve cover hose

    So I pulled the valve covers, there is oil on the side of the engine closed to the fuel does this indicate a problem with the draining that you mentioned SKISS?

  6. #6
    Join Date
    Aug 2006
    Toronto, Ont, Canada

    Default Re: Oil coming out valve cover hose

    Oil cap test at dockside is for obvious blow by issues caused by lack of good compression and oil ring problems.
    If you ran the engine while the valve covers were all removed you might notice a lack of oil from the front rockers while the rockers at the rear gush with oil. If you look for a small dia short tube this is the oil line with the o rings. If there is a problem, oil would collect from the base or top of this tube where it exits the head or enters the rocker assembly. Usually the drainage holes are not a issue but if the oil is not distributed evenly over the entire rocker assembly, then only some of the holes are draining the oil and eventually enough collects and spills out the breather. Hope this clarifies it.

  7. #7

    Default Re: Oil coming out valve cover hose

    i had a similar problem with a tamd41a, i installed a walker air seperator that solve the problem. i believe the kad43 already has a closed crankcase vent system. if it does the hose coming from the valve cover should go to a oil seperator which takes oil out of the air (blow-by) returning it to the crankcase and sending the clean air to the intake. if you have this system look at all the components for something clogged or malfunctioning.
    if you don't have a parts schematic, you can see one at marinepartspress.com good luck,

  8. #8

    Default Re: Oil coming out valve cover hose

    and also if your engine oil very thick(old), takes time to drain then will happen means oil fumes heavely from breather.

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