Oil leaking from Volvo TAMD31P Intercooler

Discussion in 'Diesel Engines' started by burke, Jul 25, 2014.

  1. burke
    Joined: May 2014
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    Location: Maine

    burke Junior Member

    Oil is dripping from the seawater drain plug boss all over the starter motor beneath. The red seal must be leaking which seals the air chamber to the HX element with the drain.

    Looks like I may have 2 problems. The seal is leaking. And the turbo is ingesting a lot of oil via the tube from the valve cover inserted into the air filter. The paper filter element is blackened with oil. Only 500 hours. If I'm understanding this correctly and I don't want to do a ring job, how about putting a sump/filter in-line to the air filter to collect excessive oil mist? How makes one?

    Thanks
     
  2. AndySGray
    Joined: Jun 2014
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    AndySGray Senior Member

    Is there a crankcase breather 'flame-trap' ?

    I used to run a much earlier Volvo and the flame trap used to block and give symptoms much as you describe. a 2 minute wash in some petrol became SOP every couple of months.
     
  3. burke
    Joined: May 2014
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    burke Junior Member

    I don't think there is a flame-trap. The 1/4" tube goes directly from a valve cover grommet into the air filter cover. Again, I'm thinking of creating an in-line oil trap in the tubee to the air cleaner which can be monitored and cleaned on some basis. Comments? Design ides?

    I'm thinking the above idea will be better than opening up the aftercooler to clean the bottom of oil accumulation, spending $200 on Volvo seals each time.

    Thanks
     
  4. AndySGray
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    AndySGray Senior Member

    http://www.marinepartseurope.com/en/volvo-penta-explodedview-7742700-21-1664B.aspx

    Does that look like yours?

    Wondering about part #25 - if missing or damaged that could be an issue.

    Now if your motor has a breather like below (I dont think they have a non return valve);-

    it doesn't have a positive crankcase ventilation system (damn californian emission control ......) so for diagnostic purposes

    Fresh air is slowly sucked into the crankcase through the breather below via the partial vacuum in the air filter tube so you could reduce the vacuum by partially clamping said hose.

    The idea is to scavenge any combustible vapours and burn them harmlessly inside the motor - you don't want those vapours in your bilge reaching critical levels but a bilge blower sucking around that breather area and venting off board would mean you could close that rubber pipe off completely.
     

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  5. AndySGray
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    AndySGray Senior Member

    But I bet that part 25 has been removed for cleaning by a well meaning previous owner and odds on a screw sheared and it didn't get replaced.
     
  6. burke
    Joined: May 2014
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    burke Junior Member

    Thanks

    I do not have the breather you pictured. Some similar Volvo models have it but not mine.

    Your schematic is the correct one for mine. Why do you suspect part 25- what is it? I'm sure mine has not been removed as the valve cover bolts are untouched.

    Question to you and others- isn't it unusual for crankcase oil to accumulate in the aftercooler? If it is normal, do you ignore it (if the seal isn't leaking?

    If oil is dripping out of the seawater drain boss, wouldn't that mean seal #11 in the schematic below is leaking? And the only way to replace it is by removing the aftercooler HX element?
    http://www.marinepartseurope.com/en/volvo-penta-explodedview-7742700-26-9829.aspx

    Thanks
     
  7. baeckmo
    Joined: Jun 2009
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    baeckmo Hydrodynamics

    Have you checked if the oil level is too high? If yes; is it "thinner" than usual (fuel blow-by from bad combustion) or is it just overfilled? Have you noticed an increased lube oil consumption lately? What about blow-by flow; remove air filter and check the flow from the vent pipe. Will you see a stream of oil spilling from the pipe end (Hold a white paper in front of the pipe opening) when running the engine?

    Actually, the air filter will also get soaked if the shaft oil seals in the turbo are gone, so it is important that you define the problem correctly.
     
  8. AndySGray
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    AndySGray Senior Member

    A picture paints a thousand words...

    I think baeckmo nailed it with the turbo shaft seals

    You're getting oil on your paper element filter on the intake side of the turbo - I admit I was looking at the crankcase breather tube as the source of that, but having seen the diagram and now I understand what you mean about the drain plug.

    my suggestion of failure (or removal) of the splash guard/shield - part 25 - allowing oil mist/spray to leave the crankcase via the breather tube is not so likely - a fine spray like that would be sucked into the motor through the intake valves and burned ( though the diagnostic is easy as baeckmo says)

    depending on access it may be easy to pull the turbo oil return pipe and make sure thats not blocked /restricted (including checking the angled fitting at the bottom) - if so it will make any less than perfect turbo seals much worse.

    There are some diagnostics in the manual or online;-

    http://boatinfo.no/lib/volvo/manuals/41exhaust-cooling.html#/24

    but it does mention that if the motor does a lot of low rev. running it is normal for some oil to accumulate in the aftercooler (CAC) - it may be that the seal 11 is not designed to be oil tight, just there to maintain the charge pressure.

    Is this a new problem or is the boat new to you - i.e. has something changed?

    Another thought is what is the grade of oil you're using vs. location - in the caribbean in summer our 'cooling raw water' is in the mid 80's (great for swimming but not for engine cooling)- many people just go by the factory stickers on the motor and put whatever it says in - but our operating temperatures are actually outside the ranges corresponding to that general factory sticker and one or two grades thicker are better options for us.

    If the oil use is excessive and a better quality (viscosity) oil or an additive don't help check if a turbo cartridge is available - often cheaper than rebuilding and replacing seals. I don't advocate switching to fully synthetic oils unless the motor has been on them from new.
     
  9. burke
    Joined: May 2014
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    burke Junior Member

    Great points. Let me respond where I can.

    This is a new boat to me. Don’t know if it’s a new problem. Only in use 2 months and only 6 hours this season by me while fixing another problem. Total 500 hours. Fresh oil, at norrnal level, no detected oil consumption and not thinned. Seawater is 65F, so the recommended oil grade is probably fine.

    Possibility of turbo seals: the pattern of the oil on the paper element does not suggest to me it's coming out of the turbo intake. I’ll try to post a photo of it.

    Sorry, but I’m unclear on how to test the blowby vent flow rate. My air filter looks like parts #44 and 45 in the following:
    http://www.marinepartseurope.com/en/volvo-penta-explodedview-7742700-25-9437.aspx Baeckmo, you are saying remove the air filter and see if oil drips from the valve cover vent tube onto a piece of paper while running (guessing; under load, cruising RPMs). Looking at the illustration, can’t I just pull the vent tube out of the air filter housing to monitor any oil flow (leaving the filter element and housing in place)?

    Thanks for the comments from the Service Manual. I hadn’t looked at the turbo section carefully.

    Thanks to all for comments.
     
  10. baeckmo
    Joined: Jun 2009
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    baeckmo Hydrodynamics

    Of course you may just detach the pipe, but there is a point in checking possible oil mist coming out from the compressor inlet at certain loadings as well (sorry, didn't mention that part). NOTE: be VERY careful that there is no loose paraphernalia (including hands..) that may drift into the inlet while running!!!

    Having both possible leak ways open simultaneously makes a comparison possible - which is the worst? Fix that one and leave the other......
     
  11. burke
    Joined: May 2014
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    burke Junior Member

    Someone explained there is a small hole drilled in the bottom of the aftercooler case for moisture blown out by the boost pressure. See attached photos. First external photo (with blue tape) is oriented as used, other is upside down.

    The pattern of oil on the air filter suggests it's not the turbo oil seal but rather ingested oil mist via the cranckcase vent tube from the valve cover. See attached photos. No sign of excessive oil dripping from bottom of the air filter housing. Only 9 years old, 500 hours, new to me, the past owner was 80 years old so possibly kept RPMs low. Any suggestions not involving rebuild? Oil additive? I don't use a fuel additive now- should I? Anything to test?

    Thanks for your help
     

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  12. AndySGray
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    AndySGray Senior Member

    My suggestion is leave well alone - there is nothing there to indicate either a current or future issue.

    Your oil in the aftercooler falls into the category of "should not need any corrective action" according to the manual (extract below), and the air cleaner is not showing enough contamination to warrant changing it other than at the factory intervals.

    Pragmatism - If it aint broke, dont fix it - (it aint broke)

    If the oil drops are really bothering you, 3M does a wonderful oil absorbing sheet which you could clip below the CAC or even tie wrap a 6x3 piece on top of the starter.
     

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  13. baeckmo
    Joined: Jun 2009
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    baeckmo Hydrodynamics

    Andy is 100% correct here. What you see on the filter outside is quite normal. Note that there is practically no oil marks on the inside of the filter element.

    The oil that has reached the intercooler comes from the turbo bearings. This engine has spent most of its life without real work. You should increase the load and let it run full load for half an hour now and then.

    And yes, Volvo intercoolers (and many others) have a leak hole that lets condensate escape before it could collect in the valve ducts.
     

  14. astat101
    Joined: May 2015
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    Location: Midlands, UK

    astat101 Junior Member

    Hi,

    On the charge air cooler subject, there is a company that manufacture diesel engine charge air coolers called Vestas aircoil A/S in Denmark (www.vestas-aircoil.com)

    They also produce water mist catchers.
     
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