Oil temperature

[Charles]

Winter has decidedly arrived up here in Canada and it's my first winter with the plane. Cabin temperature is uncomfortably low and I've ordered the baffle which goes over the opening under the left wing so we'll see how that will work. But the concern I have is with the oil temperature which the POH recommends should remain above 180F in cruise.

The baffle on the engine cowl inlet is installed but the oil temperature didn't get above 145F in my last 2 flights (OAT around -5 degrees C). My mechanic suggests installing some form of oil cooler cover (as they routinely do on C172s, apparently), but I'm a little uneasy with the idea of "modifying" the airplane for something I feel it should be able to handle as designed.

2 questions:
- Should I be concerned with the low oil temperatures? (What temperatures do you get in your DA40s?)
- If so, what would be the proper way of diagnosing the source of the problem, and what would the potential fixes be?

Thanks,

Charles

[Gary]

My DA40 oil temps runs low in the winter in spite of using the "Winterization kit " cowling air inlet cover. The concern is that the oil might not get hot enough to evaporate water in the oil. I have never had measurable water in the oil analysis so I am not worried.

[Kai]

Should I be concerned with the low oil temperatures? (What temperatures do you get in your DA40s?)
- If so, what would be the proper way of diagnosing the source of the problem, and what would the potential fixes be?

Charles, you might want to check the temperatures of other US-based aircraft in our reports-section. http://www.diamondaviators.net/reports

If you feel that your DA40's temps are too low, you might want to check for a winterization kit as Gary has.

[Tommy]

I'm running in the 135 to 140 degree range at -10c to -16c oat. I have tried the winterization kit and didn't like it. On my plane, the kit actually ran the engine temps hotter in the winter than without them in the summer. I didn't like the kit and have not used it for the last couple of years. I see no adverse affects of not using the kit in the winter.

[gsontheimer]

I do use the kit in Winter. In Summer with 20-25 °C I do get 145-150-160 °F, often below the 160 °F, if I use 55% or 65% power in cruise. In Winter at 0° to -5°C I hardly ever get above 145°F.

Gerhard

[Charles]

I did look at a few logs on the site and most show temps around 165F. Very few are above the 180F minimum recommended in the AFM, and most hover around the 165F minimum specified by Lycoming.

It seems to me that my 143F temp is too low, and I already have the winter kit installed. Perhaps I should have the thermovalve looked at....

[Gary]

I did look at a few logs on the site and most show temps around 165F. Very few are above the 180F minimum recommended in the AFM, and most hover around the 165F minimum specified by Lycoming.

It seems to me that my 143F temp is too low, and I already have the winter kit installed. Perhaps I should have the thermovalve looked at....

There is probably a test procedure to assess the accuracy of the probe. I doubt that you are really running that much cooler than everybody else without a good explanation. It is probably more likely that somebody will higher than normal temps than lower.

[Charles]

I wasn't comfortable with the temperatures we were seeing so we figured that either the oil temperature gauge was wrong or the termovalve was defective. Replacing the termovalve was the easiest thing to try so we did that and we're now seeing temperatures close to 170F even with OAT below -15C. Problem solved.

Charles

[Gary]

I wasn't comfortable with the temperatures we were seeing so we figured that either the oil temperature gauge was wrong or the termovalve was defective. Replacing the termovalve was the easiest thing to try so we did that and we're now seeing temperatures close to 170F even with OAT below -15C. Problem solved.

Charles

What is the thermovalve and where is it located? Does it have a similar function to a thermostat in a car that controls flow of coolant? What do they cost?

[Charles]

Quite frankly, I have no clue. That's just what the A&P technician told me he did and I haven't seen the bill yet. Whatever he did, it did the trick.

Could it be something like this: http://ellis-assoc.com/uploads/Anatomy_ ... atherm.pdf