The International Cessna^® 170 Association

With about 20 hours on my overhauled C-145, I have a problem getting the oil temp high enough to get the condensation out of the engine.

First off, I have a new oil temp gauge. Before installing, I checked the accuracy by placing the probe in a pot of water on the stove, along with a candy thermometer. The gauge was dead on the money.

With all the cowl openings open (not taped off), in cruise at an OAT of 40F or so, the oil temp never goes above about 160. With the sump square hole and the top louvers closed off with magic 200 mph speed tape, it goes up to 200 during a long slow climb, dropping back to 190 in cruise. This was at an OAT of 55F.

Even after a two hour flight, drops of water are on the inside of the oil cap, and a steady drip of oil mixed with water comes out of the breather after shutdown. Rust is already forming inside the filler neck, on my brand new engine!

I thought that 190 degrees was hot enough to boil the water out of the oil, after a two hour flight. I realize it is normal to see condensation mixed with the oil dripping from the breather after shutdown. It's always done that. I never saw condensation under the oil cap before, however.

Any ideas out there? Russ Farris

Finally, somebody else has the same problem I do! Even with my oil pan opening closed off, my oil temps don't go above 150 to 160 in 20-30F OAT's. And yes I have water (condensation) all the time under my oil filler cap. I have even taped off the openings for the oil screen blast tubes to try to get the temps up.

Bruce

Try taping off the blast tubes and see what the results are.

Thanks Dick, I'll try taping the blast tubes closed next. Russ Farris

Russ, don't worry about water droplets in the cap area. That's caused by a cold cap area. You'll never get rid of all areas that water may form after shutdown. (The nosecase area of the crankcase is notorious, ...you just never see it.) The oil is hot enough at 180 and above, and attempts to get it higher will result in local hot-spots.

At least one guy I know removes the oil cap when he puts his airplane away after flight,so that any moisture still vaporing around in there can vent to the outside. He also leaves the cowl-hatch above the oil cap open .

Eric