Hi all

Does anyone have any knowledge or experience about the Thermostasis oil temperature control unit for sale by Aircraft Spruce? I have seen a previous thread on this subject but it is 9 years old now and there were not much in the way of explanatory content. 

I am interested in what aircraft it has been fitted into, how the unit was mounted and plumbed and how the unit performed once installed. 

I have experience of a similar thermostatic oil sandwich plate installed on a 912 that was just plain horrible in every way so I am a little suspicious of such similar units. However, this unit seems to be much better plumbed so I am curious to find out more.

Thanks. Shelley



  • Re: Thermostasis oil temp control unit

    by » 4 months ago

    I installed the Thermostasis oil thermostat about a year ago including upgrading to a large Rotax oil cooler. I am totally satisfied with it, fast warm up and good steady temps during cruise, climb and descent winter and summer months. It is installed on my Remos GX. It is light enough enough to be supported by the oil lines alone. The left side of the regulator is plumbed between the oil tank and the pump and the right side is plumbed to the cooler which hangs just below the gearbox. Next time I'm at the hanger I can take pics and email to you if you want to see the install.

  • Re: Thermostasis oil temp control unit

    by » 4 months ago

    I have a similar unit of the same design that came with the plane.

    Again it is supported by only the Oil Lines about a foot from the Oil Cooler. No extra plumbing needed.

    Cut your existing hoses and add 4 hose end fittings. You may need to remove a few inches of hose if space is tight.


    The principal is dirt simple; It is a block of metal with two holes that pass clear through to the opposite side with no restrictions.

    The Bump that is visable on the side of the block is a thermostat the controlls a bypass channel between the two main passages.

    When the oil is cold, the open thermostst channel allows most of the Oill to take the shortcut and bypass the Oil radiator.

    As the oil warms up, less Oil is bypassed until all of it passes through to the Oil radiator just as if the thermostat wasn't there.


    The Pros:

    The Oil thermost never presents any restriction to the Oil flow.  It is either allowed to bypass or take the normal path.

    No mater what the Oil thermostat does, it can never prevent the Oil from reaching the engine.

    Even when the thermostat is Bypassing, some oil flow is still going through the Oil radiator preventing any air from trapping in it.

    There is No preference as to which way the oil flows through the thermostat unit.  The ony installation consideratoin is that the oil should pass Into the Oil radiator at the lower port if there is one, and that the Oil Exits out of the upper.  If your Oil radiator has both ports on the same edge, it can be mounted any way except with both ports Down.


    The Cons:

    You have to purchase and install it.

    Bill Hertzel
    Rotax 912is
    North Ridgeville, OH, USA
    Clicking the "Thank You" is Always Appreciated.

You do not have permissions to reply to this topic.