High oil temps

Posted In: PA-28

Participant

CHARLIE MUELLER on September 22, 2022 at 8:22 pm #21572

Steve-

I will try increasing the oil pressure as you suggest and also begin using lean to peak EGT after reviewing my pilot guide . The engine runs the same after the new cylinder. I’ll also review cowl exhaust fairing and report back in October.

Thanks again-

Charlie

Participant

wesley ballou on July 30, 2024 at 8:33 am #22668

I have a 1967 Chrokee 235B. It flew fine for the past year. Now I am experiencing high oil temperatures. Oil and filter have been changed withing the last 2 hours. Oil pressure is fine. Within 15 – 20 minutes of start up the oil temp is very near the red line. Engine runs were done on the ramp with outside temperatures of 80 degrees F. We have checked the baffles, changed the oil temp gage, the oil temp sensor, and the oil cooler. None of these remedies seems to have an effect on lowering the oil temp. Has anyone had a similar experience or have any suggestions on how to remedy the situation?

Participant

STEVE on August 3, 2024 at 11:00 pm #22670

Hi Charlie;
As I read this, it seems to say that you were getting high oil temperatures when you’re running the engine on the ground.

That prompts me to ask; “Are you also getting high oil temperatures in flight?”

Pls let me know.

Thanks
Steve

Participant

CHARLIE MUELLER on August 4, 2024 at 9:28 pm #22672

Steve-

Not sure if you were wanting me to respond or Wesley who posted more recently on high oil temps. The short answer is my peak oil temp occurs at top of climb.

I recently flew my Dakota from Naples, Florida to Aurora, Illinois in July. It was a hot day with surface temps in the 90s.

My first leg the oil temp peaked at 236 and settled down to 208, but most of the flight was 215

The second leg Montgomery Alabama to Owensboro KY (the hottest part of the day the oil peaked at 242 and settled to a low of 208 with most of the time in cruise at 218.

The last. leg was Owensboro, KY to Aurora, Illinois and the oil peaked at 227 and dropped to 210 and it was 210 for most of the time in cruise.

I have a half dozen other flights that I need to download engine data for but I think the temps were more like the last flight-peaks around 227.
Participant
STEVE on August 5, 2024 at 9:31 pm #22675
Hi Wesley, and Charlie;

I have attached a file that contains troubleshooting steps for high oil temperatures.
It’s pretty self explanatory.
One of the easier checks is removing the vernatherm (thermostatic bypass valve) and measuring the length–see page 4 of the attachment. Then submerge it in light oil that’s heated to 150 deg F. Measure it again. It should be at least 0.160 longer; if it isn’t you’ll need to get a new one.
A vernatherm that doesn’t extend won’t force oil through the oil cooler.

Another check of the thermal control system is to look at the sealing surface of the vernatherm, and the sealing surface inside the engine case to see if; 1) check for wear on the vernatherm surface and on the vernatherm contact surface on the engine case.

Lycoming Service Instructions 1316A is attached–it provides information on oil cooler causes, and solutions.

Let me know what you find

Steve
Attachments:

LYCHiOitTemps.pdf

SI1316ACoolerByPassSeatRepair.pdf
Participant

wesley ballou on May 6, 2025 at 9:44 am #23093

Steve & Charlie

I have had some success with the ongoing high oil temp issue. We increased the oil pressure. Just put a washer in the oil pump. The oil runs on the high side but is still within limits. This seems to circulate the oil so it gets through the cooler a little faster. I still have trouble in the climb with the oil temp getting to the red line. When I get to altitude it seems to settle into the high normal range. This is when outside air temperatures are in the low to mid 80’s. My concern is that when it gets to be summertime here in Texas and temperatures get in the mid 90’s and above, I will not be able keep it within limits until to altitude. I have had thoughts of putting a higher capacity oil cooler in. Additionally, I was looking into moving the oil cooler to a location that it would get better airflow like some of the newer model PA-28’s. I was also looking into the possibility of increasing the vents on the bottom of the cowling or possibly installing a cowl flap to increase airflow until I can get to altitude and power back to cruse power. Any thoughts on any of these suggestions?

Thanks for taking the time to read this and any feedback you could provide would be appreciated.

Thanks, Wesley