Low Oil Temperature Management

[Becky Teerink]

Here is our recommended technique for managing low oil temps, particularly in the winter months.

We recommend installing aluminum tape on the front of the oil cooler to reduce the air moving through it.

1) Remove top cowl. (It is possible to get the tape on the oil cooler from the front without removing the top cowl if you have smaller arms and some flexibility. This is easier in the long run as you don't have to clean and re-apply silicone.)

2) Remove the screws, top front and bottom rear, that hold the oil cooler on. Some a/c have silicone as needed to seal between the cooler and the baffle. Clean old silicone off.

3) Lift oil cooler up and install aluminum tape as needed, but don't cover the entire inlet area. We found 1/2 to 2/3 covered worked well.

4) Install oil cooler, replace screws, if needed re-silicone between cooler and baffle.

[glickle]

FYI I am now encountering outside temps here in Florida of over 85 degrees and still have about 3 inches of tape on the front of my oil cooler and works well to hit between 180-200 degrees pretty consistently. During the colder trips/months I had to cover half of the oil cooler to get over 180 degrees and could access the front of the cooler through the right side intake. So bottom line is the oil cooler really works well for us southern climate guys as compared to my S2 which I could have used more cooling as often saw temps aproaching 220. Regards Gary

[John Hodges]

Doesn't the oil cooler have an in-line thermostat? And what's wrong with 160 anyway? Even at 160 on the gauge, and lower, the instant oil temp on the heads, pistons, cyl walls, and probably other places is considerably higher.

[turbopilot]

Doesn't the oil cooler have an in-line thermostat? And what's wrong with 160 anyway? Even at 160 on the gauge, and lower, the instant oil temp on the heads, pistons, cyl walls, and probably other places is considerably higher.

Here is the theory of the case for the Continental world. Still trying to find out if it is the same in the Lycoming /ECI world. Oil temperature in TCM engines is measured after the the oil cooler. Optimum oil temperature goal is to have the temperature above the boiling point of water somewhere in the circuit in order to drive off water associated with the combustion process. If you continuously run the motor so that water accumulates in the oil then the motor will experience internal corrosion.

In Continental motors it is know if you get the oil temperature indication (ie after the cooler) above 180 dF that the inlet oil temperature to the oil cooler will be above 212 dF (or lower depending on altitude).

[TheCubWorks]

I can add to Bob's post.

The oil is a multi viscosity meaning as it heats up the carbon chain unfolds and increases the size of the oil molecule. This does wonders for the engine as the larger oil molecules pad the bearings better, and float the piston rings on the barrels. An example I read once is like a boat bobbing up and down on a lake of oil, the boat is bobbing due to cyclic loading of the compression / ignition event. When the oil has less viscosity it runs away form the boat easier allowing the boat to touch the bottom, add to that the oil molecules themselves don't have the ability to absorb the load, the carbon chain is not as springy when it is not unfolded. At that point oil does very unnatural things, the molecules tend to line up uniformly and become sticky or something other than lubrication, so the boat is grounded on slime not bobbing on water.

So what happens when we run oil temperatures at 245deg.f? Nothing,

How about 275deg.f? the oil overheats at the source of heat, thermodynamics teaches us that there is a temperature differential that must exist over a period of time for heat to transfer. Therefor the source of heat is significant, I say it is the source of heat that is the problem not the oil temperature!