VAF Forums

VAF Forums (
-   RV-14 (
-   -   Oil Temps too High (

kdedmunds 05-29-2019 04:39 PM

Oil Temps too High
I have flown my RV14 for close to 50 hours. Most of that time has been in the winter when temps were a little cooler. On an aggressive climb i would get oil temperatures in the 220s but leveling out I would get back to 180s and could lean the fuel injected IO 390 to about 10 gal per hour. Now Im climbing at 300 ft/min to reach altitude and forget leaning at all. I can keep the temps in the high 190's running the engine at full rich but as soon as I lean I start climbing in temperature. The oil cooler is standard for the engine and I know there are 14's out there that are running with oil temps just fine. Any suggestions?

bkervaski 05-29-2019 05:08 PM

Did you seal your baffle so no air is escaping? There are a number of areas that need filled with RTV.

Bavafa 05-29-2019 06:25 PM

Hi Ed,
For a better comparison with other 14s, perhaps a bit more info would be useful. What are the OAT for those temps and what is the target altitude?

As a reference, my temps have also gone up a fair amount than during the winter time but not nearly as high as you are reporting.
On my last cross country trip, I was able to climb to 12000 ft from sea level at 700-800 fpm with the OAT of 86 but my temp got as high as 212. During slow flight (practice approach) I easily see temps in the 200+ range but if I speed up to the normal cruise speed, it comes back down quickly. My cruise speed temps are in the 185 range unless I am high up and cooler temps.
As mentioned above, make sure all baffles are sealed well including the oil cooler.
I miss my oil temp during the winter time.

vic syracuse 05-30-2019 04:51 AM

I really don't think there is anything wrong with those temps. Hitting 220 or so in the climb in the summer is fine, especially since you are getting back into the 180's in cruise. Make sure the quantity is at 6 qts.
I saw the same thing with the factory demos, and the first time I saw it climbing above 210 I was a little concerned, but then I started experimenting with full power climbs to 10K' in the Atlanta summer heat and noticed it cooled right back down very quickly, so I quit being concerned about it. I also think as you get more time on the engine they will come down some as well.


DanH 05-30-2019 06:01 AM

The IO-390 operator's manual is clear. For maximum engine life, the desired oil temperature is 185F.

No one, including the staff at Vans, would consider this performance acceptable:


Originally Posted by kdedmunds (Post 1349621)
Now I'm climbing at 300 ft/min to reach altitude and forget leaning at all. I can keep the temps in the high 190's running the engine at full rich but as soon as I lean I start climbing in temperature.

There is something wrong. Happy to help, but we'll need more information, photos, etc. ID the ignition system and timing, and post a few photos with the upper cowl removed.

F1Boss 05-30-2019 07:47 AM

I know the 14 has a wider fuselage, so the cowling is from a different mold to allow it to fit - but are the inlets also reworked to allow for the larger engine? If all the other recommended checks and fixes are done, and the temps still are not what they should be - it could be time to add a set of (non-patented) Dan Horton Inlets - sure fixed all temp problems for me!:)

Yes, the plane should be able to climb at ~130KIAS all the way to cruise altitude with no problems.

Carl Froehlich 05-30-2019 08:18 AM

Like Dan said, you have problem(s) to investigate. With a stock setup you should have lower temps. I'd start by looking for obvious stuff, like a blockage in the air going to the cooler. Leave a rag in the oil cooler plenum?

Side note - I have used the Airflow Systems 2006X cooler in two airplanes and recommend them over the one Van's provides in their Firewall Forward kit.


Bavafa 05-30-2019 08:27 AM

From my Lycoming manual
"Oil Temperature: The maximum permissible oil temperature is 235?F (118?C). For maximum engine life, the desired oil temperature should be maintained between 165?F (73.8?C) and 200?F (93.3?C) in level-flight cruise conditions."

In checking with other RV14 drivers, temps in the 210 range in the steady climb and 185-195 during cruise has been the common temp.

rvbuilder2002 05-30-2019 09:42 AM

During development of the RV-14 (and the FWF kit specifically), flight testing was done in relatively hot temps (90-95 F.) by doing a take-off from 160 ft MSL and climbing to 10K feet at Vy (best rate) for the entire climb, with the aircraft ballasted to gross weight.

The highest peak oil temp I recall was just over 220F. This would occur at some point during the climb and the temp would begin to drop before reaching 10K feet.

Keep in mind that this was a climb to 10K feet using best rate of climb speed for the entire climb. This is not a typical operation mode. Using a cruise climb airspeed has a very small impact on ROC but a very large impact on cooling. If traveling cross country it also gets you down the road more quickly and provides for a higher overall miles per gallon on a cross country trip.
I personally cruise climb (and descend) at 500 FPM unless there are terrain constants.

New engines will tend to run a bit hotter in oil temp. Some engines will have temps continue to reduce further going out beyond 50 hrs, but in this case I would be searching for issues that would be allowing air leakage from the baffle system.

kdedmunds 05-30-2019 10:59 AM

The engine does have 250 hours. I bought the plane didn't build it. Last Thursday I was cruising at 6500ft with an OAT of 73. Full rich the oil temps showed 198. I leaned to 10.5 gal per hour and the temps started climbing slowly. I went back to full rich at 215. I will check for leaks as well as air blockage on the oil filter.

All times are GMT -6. The time now is 03:01 PM.