Transmission oil cooler location

Discussion in 'Gas Engines' started by missinginaction, Apr 5, 2018.

  1. missinginaction
    Joined: Aug 2007
    Posts: 720
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    Location: New York

    missinginaction Senior Member

    I'm finally getting around to installing a proper raw water strainer for my cooling system. I'll add the strainer directly downstream of the seacock. I use a Sherwood e-35 raw water pump and the transmission oil cooler is squeezed in between the raw water pump and the thermostat housing. It works fine but it's pretty crowded between the Sherwood pump, fuel pump, oil cooler, hoses, spark plug wires......makes servicing more difficult than it should be.

    I'd like to move the oil cooler UPSTREAM relative to the Sherwood pump. I've looked in my Borg Warner manual and there isn't any recommendation one way or the other. What I'd end up with is water that flows as follows: Intake, strainer, V-drive, oil cooler, raw water pump, thermostat housing, through engine and out to manifolds and finally exhaust. BTW, I'm using good Shields/Trident wire reinforced hose.

    Perhaps I'm over thinking this but is there any reason that the oil cooler needs to be downstream of the raw water pump?

    Thanks, MIA
     
  2. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    The main problem with having negative pressure on the coolers, is that they may end up with dry spots. The positive pressure drives the water into all the cavities and drives the air out.
     
  3. missinginaction
    Joined: Aug 2007
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    Location: New York

    missinginaction Senior Member

    Thanks for the reply Gonzo. I finally found a Mercruiser article that showed the cooler mounted upstream of the raw water pump. I'm seeing it done both ways. For my little small block and Velvet Drive set up I can't see that it will make much difference either way. There have been about 50 views and you're the only one who commented. I suppose if there was any serious problem with this I'd have heard something by now. Thanks again....MIA
     
  4. baeckmo
    Joined: Jun 2009
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    Location: Sweden

    baeckmo Hydrodynamics

    I think Gonzo is absolutely right here. The pump should operate without head losses at the suction side, i.e. all cooling components to be installed downstream pump. Most strainers do not stop fine mud from entering the system, and it will settle in the coolers, increasing the flow resistance, reducing the flow, increasing the water temperature into the pump; all of which is detrimental to the pump impeller.

    With coolers in the pressure region, the impeller will last longer, and mud build-up is less probable (if partial blockage occurs, flow velocity increases when it happens in the pressure-side. If occurring in a suction-side cooler, it will cause cavitation and reduced flow). So, do it right from the beginning!
     
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  5. missinginaction
    Joined: Aug 2007
    Posts: 720
    Likes: 54, Points: 28, Legacy Rep: 512
    Location: New York

    missinginaction Senior Member

    Thanks for the insight baeckmo. As I said I'm seeing it done both ways but what you say makes sense. If I understand correctly the pressure of the water coming out of the raw water pump would tend to scour out any debris that might be passing through the oil cooler, such as fine silt. The oil cooler is currently directly downstream from the SHerwood pump. I was thinking of moving it to make some other routine maintenance jobs easier. Based on what you're saying the original manufacturer (ThermoElectron) did it correctly. I can live with it. Thank you for sharing your knowledge. MIA
     
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