Oil Cooler

[170C]

Noticing in the ad for the 48 170 For Sale that it shows to have an oil cooler. I have a friend (new member) with an O-300C that has about 1400 hours smoh. It has one of the oil temp gauge with just green & red markings. While no tests have been performed to determine the accuracy of the gauge, on these 90 degree, Middle Tennessee days after a couple of takeoffs the gauge shows to be just into the RED. Are there oil coolers available for O-300 Continentals?

[KS170A]

This one is the only one I know of. Your friend's oil temp is probably right, unfortunately.

A gauge without numbers is almost useless, as depending on which oil he is using he could go past the standard 225° limit to 240° by using 100W (SAE 50) oil.

[Bruce Fenstermacher]

Oil coolers where available for OTHER aircraft. According to the IPC only used on the C-125 and C-145-2 but not the 0-300 series. They are used on the Swift for example when it is converted to C-145. I wouldn't be surprised if they could actually be used with the 0-300 but not marketed for them.

They are not necessary on a 170.

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[KS170A]

They are not necessary on a 170.

I'm assuming you mean that for certification purposes. Seems like from the number of comments and articles regarding high oil temperature, perhaps not "necessary" but a pretty good idea.

[GAHorn]

The majority of interest in oil coolers for our 170s is due to several things:
1- Inaccurate oil temp gauges
2-Poor-fitting or missing engine cooling baffling.
3-Leaking exhaust pipes heating pushrod tubes.
4-Out of date operating info (later type cert. on this engine allows higher oil temp to 240-F when SAE 50 oil is used.)
5-Installation differences from other aircraft which the operator has previous experience leading him/her to incorrect conclusion.

Bruce is correct: a properly maintained 170 with 145/O300 engine does not need an oil cooler.

Many operators of this engine in other aircraft complain of too COOL oil temps and worry about condensation/water in their oil not being boiled off. It's a humorous observation to read those opposing operating problems. They go to all kinds of lengths to increase their oil temps while 170 owners do the opposite.

The bottom line is : You can largely ignore your high-end oil temps, especially if you use SAE 50 straight wt oil, if your cowling/baffles are in good condition.