My Continental O-200A is plagued by hot oil temperatures even in cruise flight. After a few minutes of climb, my Dynon D10 shows oil temperatures in the range 90-100 degrees Celsius, which stay there in cruise flight. Now that it’s summer, I often see 100-107 degrees Celsius at 2550 RPM, which is quite close to the limit stated in the Continental engine manual (125 degrees Celsius). That can’t be healthy, no?
To rectify that, I already installed “blast tubes” redirecting ambient air to the oil reservoir, without much change. My mechanic thinks that a superfluous gear from an old installation of the starter in front of the cylinders should be removed to improve the circulation. However, I can’t believe that this would rectify my oil temperatures.
I’d rather install an oil cooler. He recommended me to buy this one here: https://www.stevesaircraft.com/oilcooler.php. However, this seems to be an aftermarket part, and much smaller than other oil coolers. Do you have experience with /opinions about this oil cooler for the O-200A, or can you recommend me another one?
Before going for the oil cooler you may check the calibration of your Dynon sender right after landing by quickly comparing the indication with a very long mercury thermometer rated for say 150*C,tied with a thin fishing line which you will drop into your oil dipstick hole.Additionaly you may suspect broken piston oil ring if your consumption is high.Finaly you may convert to 100W ashless monograde.What about your oil pressure?Is the oil pump OK?
My thought would be to get the mechanic to remove the surplus gear and see if it makes a difference. What is the downside apart from maybe 2hrs work?
Photo of my oil cooler (for an Archer 2) 1/3 blocked off as in the winter my oil was otherwise far too cold in the cruise. This helped a little but in the end I blanked it all off and then got some sensible winter figures ie for 2C OAT oil temps 80-85 C varying as to whether it was the first flight of the day and payload. As the OAT rises in the spring the oil was near to 100C with OAT 12C. So then I made a 2/3 restriction and that gives an oil temp of 88C for an OAT of 18C. In the summer with an unrestricted cooler and OAT 23C Oil Temp is approx. 84C. In the unrestricted mode as the OAT drops say to 6C the oil temp drops to 70C.
The moral of this is you have got to put some work in all the time if you are using my crude method!
All oil temps taken from the cruise. I have an EDM 830 recording the data.
There is a placard in my aircraft saying that a blanking plate should be fitted in winter but try as I did I could not get the part number from Piper and anyway a full blanking plate is as you can see of limited value seasonal-wise
I would have to measure the cooler front to be more specific but someone on the forum might know, and that might help you evaluate your particular need.
My cooler is bog standard for an Archer 2 as far as I know.
MedFlyer wrote:
Before going for the oil cooler you may check the calibration of your Dynon sender right after landing by quickly comparing the indication with a very long mercury thermometer rated for say 150*C,tied with a thin fishing line which you will drop into your oil dipstick hole.Additionaly you may suspect broken piston oil ring if your consumption is high.Finaly you may convert to 100W ashless monograde.What about your oil pressure?Is the oil pump OK?
Good idea, I will try to check oil temp. I don’t have a long mercury thermometer at hand — would a digital laser infrared thermometer like this one do, if I point it into the oil dipstick opening?
The oil temperature display on the Dynon is quite jumpy — about 2-3 times per second, the temperature jumps by about 3-7 degrees Celsius. Does that seem normal?
I’ve had a top overhaul about 40 hours ago, and oil consumption is about 0.1 lph. So I’m currently still using mineral oil (Total Aero 80). I usually fill up to 3-3.5 quarts. (My dip stick has a min of 2 quarts, and a max of 4 quarts.) I will switch to synthetic oil in some 10 hours. Would that possibly improve oil temps?
Cylinder head temperatures (about 120-160*C) and exhaust gas temperatures (about 700-800*C) shown by my Dynon seem reasonable, no? Also indicated oil pressure is in the green (about 3 bars), albeit on the lower side of the green range.
Stanley wrote:
My thought would be to get the mechanic to remove the surplus gear and see if it makes a difference. What is the downside apart from maybe 2hrs work?
I was quoted about EUR 500 for that work (including a replacement of the “propeller bolt” for about EUR 100 and about 6 hours of labour). The oil cooler would set me back about EUR 1’500 (including EUR 900 in parts). So my thinking was, the former might improve the oil temps, whereas the latter is almost certain to improve them. Or am I thinking wrong?
BTW, is it common for such engines to have no oil cooler?
Zorg,
I can see your logic regarding the significant price of removing the surplus kit and the likely result.
You can easily check the oil temp/OAT correlation before engine start at the beginning of the day, to see if you get agreement at low temperatures.
The idea of dropping anything down the dipstick hole frightens me.
My first move would be to have the oil cooler ultrasonicly cleaned, if some of the galleries in the cooler are blocked it simply won’t work as well as it should……. or am I misunderstanding and you don’t curently have an oil cooler ?
These engines don’t usualy have problems with high temperatures, have you had any other problems like oil leaks from cylinder base seals or crank cases that have recently resolved ?
I’m not sure that I would get too worried about any temperatures that stay within limits as long as I was confident that the indication system was correct.
The thing that would trouble me would be low oil temperatures especially not getting above 180F during winter flying so you need to ask if fitting the after market cooler will over cool your engine in the winter ?
Can the oil temperature sensor be easily removed? Then dipping it in a mug of boiling water would give a good high temperature correlation point.
Xtophe is half way to solving the calibration problem.
To check the sensor put it into a metal container and use a heat gun to heat the container and a reliable thermometer in the oil, ( or a laser thermometer ) this way you can test the indication system all the way up to the engine red line.
Zorg wrote:
Good idea, I will try to check oil temp. I don’t have a long mercury thermometer at hand — would a digital laser infrared thermometer like this one do, if I point it into the oil dipstick opening?The oil temperature display on the Dynon is quite jumpy — about 2-3 times per second, the temperature jumps by about 3-7 degrees Celsius. Does that seem normal?
Why not ,if this Laser tool gets fit with a long thin probe to pour it inside your dipstick hole.But before that,first check it into boiling water and see the readings.
Jerky indications,Yes I also had even with analog Westach instruments.Created by electromagnetic interference from the magnetos.I had to modify the cables routing.Then,indicators stayed quiet.
Another issue I thought: After OVH we have higher temps and consumption due to friction till things settle.Did you observe this elevated oil temp AFTER OVH ? If Yes,wait and see and DONT baby the engine.
