Oil cooler winterization for 172 O-320

Discussion in 'Maintenance Bay' started by Pedals2Paddles, Jan 7, 2015.

  1. Pedals2Paddles

    Pedals2Paddles Cleared for Takeoff

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    Anyone have suggestions for a winterization plate for the 172 O320-E2D oil cooler? I've been reading a lot different ideas. Some suggest putting it on the cooler. Some suggest putting it on the top of the inlet for the oil cooler air hose and blocking off about 60% of the air.

    I would also plan to check the accuracy of the oil temp gauge in hot water before doing anything.
     
  2. Stewartb

    Stewartb Final Approach

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    I use duct tape on the cooler.
     
  3. Pedals2Paddles

    Pedals2Paddles Cleared for Takeoff

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    On top of it to block air flow through it?
     
  4. Henning

    Henning Ejection Handle Pulled

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    Cover the cooler with the tape strips perpendicular to the tubes rather than parallel to prevent sludge formation if you use the tape method. Yes, you are restricting airflow and cooler surface area exposed.
     
  5. Pedals2Paddles

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    How does the direction of the tape cause or prevent sludge formation??????????
     
  6. Henning

    Henning Ejection Handle Pulled

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    Because if you cover the entire length of a couple/few tubes lengthwise, it causes an uneven heating/cooling across the cooler which causes an uneven flow with very hot and very cold oil mixing in the output side tank before the vernatherm. You end up building sludge there. Going across the tubes ensures even cooling and flow across the cooler.
     
  7. Stewartb

    Stewartb Final Approach

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    It's amazing that engines have oil coolers to take the hot oil, cool it, then mix it back into the hot.

    I run tape along the diagonal bar that's on the face of my cessna's cooler. No reason other than it's easier when it follows the bar. Lots of years, no problems. On my old PA-12 that had a rear cooler for an 0-320 I'd cover 100% of the cooler in winter. My Cessna gets about 70% covered. Lots of guys prefer aluminum tape because it has a very thin layer of adhesive so it doesn't leave much goo behind when you pull it. My duct tape has thin adhesive. Not all duct tape does so be aware.
     
    Last edited: Jan 7, 2015
  8. Henning

    Henning Ejection Handle Pulled

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    You can do nearly anything at least a half a dozen ways. Only one will typically produce the optimum result. A diagonal stripe is halfway between and not a particularly bad one to retain more heat than a single vertical stripe since the heat will concentrate at the middle and all the tubes will have sufficient coverage to prevent over cooling and condensing out the sulfuric acid and water in the cooler.
     
  9. Stewartb

    Stewartb Final Approach

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    I learn new stuff every day. All my years in Alaska and I've never heard the sludge story. Everybody I know uses duct tape on coolers. Go figure. What about winterization plates? You must have some comments about those?
     
  10. Henning

    Henning Ejection Handle Pulled

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    I have always used duct tape when I needed to operate in cold weather. I suppose the plates are fine, but unless I bought the plane with it, I wouldn't spend the money. I just put a strip or two across the cooler perpendicular to the tubes. It's no more effort really to get the optimum result.:dunno:
     
  11. poadeleted20

    poadeleted20 Deleted

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    Why do you feel you need one? Is your oil temp not getting over 160F?
     
  12. Pedals2Paddles

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    It has been staying left of center. It doesn't have numbers across the range. The only temp it actually has a numeric value for is 75 and 225 (min and max). If it is linear (?), middle would be 150. Therefore, one could interpolate that it is indeed less than 160. And it takes forever to get there.

    I'd like to do some calibration with a bowl of hot water to actually see what the gauge thinks before doing anything. My understanding is 180 degrees is optimum for cooking off the moisture in the oil. 140-160 is a warm bath, not hot enough. I'm thinking test it with the water at 180, and mark the gauge with that point for reference.
     
    Last edited: Jan 7, 2015
  13. coloradobluesky

    coloradobluesky En-Route Gone West

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    Factor in that you may forget to take it off if it warms up. Better too cool, than too hot IMO.
     
  14. Henning

    Henning Ejection Handle Pulled

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    Start with one stripe of duct tape about 1/3 way across the oil cooler. If that isn't enough place another stripe at the 2/3 position. That should be sufficient (might even need to use a partial width second strip) to all but the most extreme -40° type days.
     
  15. Pedals2Paddles

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    True. But best is the correct temperature. There are three of us and I'm 100% confident that won't happen.
     
    Last edited: Jan 7, 2015
  16. poadeleted20

    poadeleted20 Deleted

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    Then you probably do need to do something. I'd consult Lycoming tech support (800-258-3279 or 570-323-6181) for suggestions. However, I would not go modifying the oil cooler without some approved data and an A&P's signature in the maintenance records.
     
  17. Stewartb

    Stewartb Final Approach

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    Oh, brother. Here's a quote from Lycoming cold weather operating instructions. As if you need permission to operate your engine correctly.
    Source: http://www.lexingtonflyingclub.org/lycomingatextroncompany-coldweatheroperations.pdf
     
    Last edited: Jan 7, 2015
  18. Henning

    Henning Ejection Handle Pulled

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    Yeah, this isn't exactly rocket science. Just block off some airflow, preferably as evenly across the cooler as you can, until the oil temp rides where you want it. When it gets warmer, peel some off.
     
  19. Dan Thomas

    Dan Thomas Final Approach

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    If the Vernatherm is working right, you shouldn't need an oil cooler blocking device unless it's really, really cold. Cessna has winter kits that close off part of the cooling air inlets at the front of the cowling, and all the temps will rise nicely if you use those. They go on at temps below -7°C.

    For the 172 with the Lyc, the usual way to close off the oil cooler airflow when the weather is extra cold is to screw an aluminum plate over the outlet hole in the right rear baffle. Most plates I've seen have a one-inch hole in them to keep a little bit of air moving through. The hose is a three-inch, so a one-inch hole really cuts down on the cooling flow.

    Dan
     
  20. Pedals2Paddles

    Pedals2Paddles Cleared for Takeoff

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    OK. New question then. How does one determine if the vernatherm is working.
     
  21. Stewartb

    Stewartb Final Approach

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    Don't expect the vernatherm to keep your oil warm in winter. They don't.
     
  22. Henning

    Henning Ejection Handle Pulled

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    The advantage to blocking the cooler is it keeps the oil flowing through the cooler.
     
  23. Henning

    Henning Ejection Handle Pulled

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    Normally you will see the jump in oil temp if you are watching for it.
     
  24. poadeleted20

    poadeleted20 Deleted

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    I'm pretty sure his engine is equipped with a thermostatic bypass valve (aka "vernitherm"), so closing off part of the oil cooler would not be appropriate under the instructions you quoted. Unless you know the engine is not so equipped, ask Lycoming before you go doing something unauthorized.
     
    Last edited: Jan 7, 2015
  25. poadeleted20

    poadeleted20 Deleted

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    Your mechanic pulls it out at tests it. If it's working properly, you should not need any oil cooler blocking. If it's not, you fix it before you consider messing with the oil cooler inlet.
     
  26. Stewartb

    Stewartb Final Approach

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    Bunk. His engine is acting perfectly normal for winter. Even with a vernatherm, although he my have a viscosity valve. Either way the tape solution is a simple and infinitely adjustable solution, pioneered by thousands of northern climate pilots for lots of years. Y'all can turn this SIMPLE topic into a ****ing match if you choose. My advice is a pirep. And I'll keep on doing it.
     
  27. poadeleted20

    poadeleted20 Deleted

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    And authorized by what FAA approved data?

    Don't let me stop you from doing whatever you please. Just please don't suggest to others that it's OK to make unauthorized modifications to their aircraft without appropriate approval.
     
  28. Pedals2Paddles

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    Don't worry Ron. I'll use my FAA PMA duct tape. The same stuff I used to close off the air vents.
     
  29. poadeleted20

    poadeleted20 Deleted

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    :rofl:

    Seriously, if you do have a vernitherm, this shouldn't be happening unless you're based at Point Barrow or something like that, so either check the maintenance manuals on the plane for guidance or ask Lycoming before you go taping over the oil cooler. And be real careful about the tape you choose, as getting that gummy stuff all over the vanes could be a real mess to clean up in the spring. I think most folks use aluminum tape, not fabric duct tape. You ever seen what happens when you put duct tape on something that gets hot?
     
  30. Pedals2Paddles

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    Yes. And in fact we'll probably use actual aluminum.


    << Sent from my mobile device at 0agl >>
     
  31. Stewartb

    Stewartb Final Approach

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    For guys who battle oil temps you might look at Van's Aircraft's ajustable oil shutters or Dan's Aircraft's approved Supercub adjustable oil cooler doors and see if you can get a field approval for the install. Control oil temps year-round from the pilot seat. Very nice. And evidence that you aren't the only one experiencing too-cool oil temperatures! Even with a vernatherm!
     
  32. nrpetersen

    nrpetersen Line Up and Wait

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    Our 172M (1975) did not have a vernatherm from Cessna when new. Instead we used a foam plug in the 3" cooling duct. The plug was cut from a shipping container packing for an FAA TSOed instrument, so we assumed it was approved too. It raised the oil temp maybe 40 degF, and when we forgot about it one spring, the oil temp did get well up into the green. Otherwise it was a very cold blooded engine for the 1800 hrs we owned it.