This is an email I sent to Reiff. I'm interested in other input from you:


I have an XP System on an IO-520 in a Cessna 185. I find that, if I preheat for a relatively short time (4-6 hours), the oil and cylinders are all at an acceptable temperature. However, after takeoff, the oil temperature will drop, sometimes down into the 70's. Over the following few minutes (maybe 5 or 10), the oil temperature comes back up to three digits.

I'm assuming this happens because I haven't heated the oil cooler, so when the vernatherm opens, cooler oil flows past the oil temp probe.

Does that sound like a reasonable explanation? If so, would an oil cooler heater be the solution? Lastly, do I need any additional connectors to add the oil cooler heater to the XP system?

Anticipating questions: I have a good quality cowling blanket and cowl plugs, and I always park with the cowl flaps closed. When it's cold, I cover a large fraction of my oil cooler with aluminum tape. I'm using Phillips X/C 20W-50.

That would be my guess. Reiff sells an oil cooler pad.

Kurt

Yup, I would agree that that is what is happening.

I look for this temp drop before I do my run up. No matter the outside temp, during the initial run, usually takes 5 to 10 minutes. The oil temp will steadily rise, then at some point start to slowly fall, then steady and climb up over 100°. I wait for this to happen before running up and testing things.

I agree with the others. I wouldn't worry about it. The oil mixes pretty fast, and that will almost certainly happen prior to takeoff.

An oil cooler heat pad would likely help. Is it necessary? I operated an IO 520 in the Upper Yukon Valley in winter, including overnighting in Beaver or Ft Yukon, where we had electrical outlets. Never worried about it, and those temps were no joke cold.

MTV

Thanks, everyone. It’s good to be validated. No reply yet from Reiff.

I would suggest your symptoms are the result of a lack of time for the heat to propagate throughout the entire engine. My concern is this; if the cooler, which is made of aluminum, and an excellent heat conductor, is not properly warmed, how warm do you think your crankshaft and main bearings are which are made of steel? Think frozen turkey…high heat of short duration provides false security as it only warms the outer surface to which it is applied. It takes time for that applied heat to reach and then bring the core to an acceptable temperature for operation through the process of conduction. I also suggest the use of an insulated propeller cover as those long blades make an excellent radiator releasing heat directly from your crankshaft which has a hard enough time being warmed through its only available process which again, is conduction.

TR