Hi Oil Temp issues

[Puddlejumper]

Our 170B has had hi oil temps from day 1. We now have 50 hrs on it and at 2400 turns at 85-90° oat it runs at and in the red. On a warm day at 100'msl I have to pull it bk to 2300 or lesss to keep it Jst under the red. We had a 170A in the past and never experienced this. It ran hi but never in the red. I've been running Phillips XC 20-50 oil in it. I decided to go to aeroshell 120. Straight 60W to see if it helped. However all my oil suppliers in the area quit carrying it so I haven't tried that yet. I used to own and fly heavy warbirds and ran Phillips XC25-60 and never had a temp problem in those higher horse power engines. I know there's a cooler we can buy and install but that's an expensive pain. And the C145 was made to run w/o one. And this thing has not had one in 65 yrs. does anyone have any ideas or suggestions?
Thanks
Puddlejumper.

[sfarringer]

Have you verified that the gage is accurate?
Have you verified that the two blast tubes are aimed directly at the lower end of the accessory case?

[Puddlejumper]

I haven't tested the guage yet. I'm probably going to do that nxt. The blast tubes are pointing to the area where the screen is. And it has an oil filter kit installed as well w a heat sink wrapped around the filter. Thanks for the reply.

[N2625U]

I ran across this some years ago and it does explain a few things about the O300 oil system and design.
Continental was opposed to external oil lines on their engines, and the "C"-series of engines was designed without them. Although an oil cooler design was produced by TCM (Continental Motors Corporation), Cessna was opposed to using it, probably for price considerations. So the C145/O300 installed in a Cessna runs hotter than the same engine in a Fairchild/Stinson/etc.. It also runs cooler in a Swift due to the updraft cooling.
Why would updraft cooling help? For one reason, the oil sump gets a nice first-chance at the cool air. But another major reason is because the pushrod tubes, being sheet-metal, and because the Cont. engines pump relatively high quantities of oil to the rocker boxes (much more than the Lycomings because of the better hydraulic lifters that Cont. uses) that subsequently runs back down those tubes to the sump, ...those pushrod tubes act as oil coolers and on the updraft cooling systems they also get a first-shot at the cooling air.
On a downdraft cooling system such as on our airplanes, the pushrods aren't in such a good position, as they sit downstream of those nice warm cylinders. Nonetheless, they still perform a function of cooling. And that's the problem.

If your exhaust flange gaskets leak, or if your exhaust riser clamps leak and spray hot exhaust onto your pushrods, a surprisingly large increase in oil temperature will result. So look for signs of exhaust blowing on your pushrod tubes.

There is not too many reasons for a 170 engine (C145/O300) to suddenly start running much hotter than 210-220 F. The most common reason for a sudden change is a faulty gauge. The next most common reason is a leaking exhaust flange. The third reason is faulty cooling baffles. The fourth reason is a broken or stuck piston ring, which can be detected with a compression test and subsequent blow-by into the crankcase.

Even a C145/O300 engine that has run all it's life with oil temps at or near redline will make TBO as often as other engines that run much cooler. The high oil temp does not seem to hurt the C145/O300 as much as it does some other engines. One reason for that is due to the location of the oil temp probe. Our oil temp probes are located at the oil inlet to the engine (at the oil screen.) Most other engines measure their oil temps at the outlet of the oil cooler. That's why they commonly indicate oil temps in the 180 degree range. Therefore it's not appropriate to compare the C145/O300 engine oil temp indications to other engines. If you'd measure the oil temps of most other engines at the inlet of their oil coolers their temp readings would be frightening.
So,...run SAE 50 wt oil in warm weather (above 40 degrees F) and SAE 30 in cooler weather (below 40 degrees F) order to take advantage of the higher 240 degree oil temp redline. (I've never seen SAE 30 aircraft oil, personally. Interestingly, SAE 40 oil is never approved for 240 degrees in our engines, apparently because it's not approved for use below 40 degrees F.)

[c170b53]

Does puddle jumper, also occasionally jump in and out of puddles ( float ops) ?

[Puddlejumper]

Thanks for the suggestions. All good info. I'll try all recommendations. And re puddlejumper, that was a call sign my late father-n-law gave me when I was 17 flying around in my Cessna 140 about 46 yrs ago. When I had several war birds a few years ago I was given the call sign "Shug" since my last name is Sugarek. We had a P64 (bet you've never seen one of those) and a Japanese Kate Torpedo Bomber that we flew w the CAF "Tora Tora Tora" group for a while.

[GAHorn]

N2625U pretty well describes the issues on this subject. Chances are that your oil temp gauge is not accurate or you have an exhaust leak and/or cooling baffle issue. There's very little reason othwise for this engine to operate in the "red".... except to say that if your gauge is the old 225-degree gauge then it's not very useful considering the TCM type cert authorizes 240-Degrees using SAE 50 wt oil. (not 20W50.... but STRAIGHT SAE50).

TCM recommends SAE 40 oil in universal service (oil temps running 120-220 F) and SAE 20 (good luck finding that) when oil temps run below 120F). RE:page 7 of the Operators Handbook.

Personally, I run AeroShell 100 W year round and pre-heat in winter below freezing.

[Puddlejumper]

Thanks to all who have replied and made suggestions. I really appreciate it.
I will change from Phillips XC20/50W and go to straight awroshell 100 50W. Is there a reason straight 50w is recommended over 20/50 multi-viscosity?
Also re the question about the F&M oil filter adapter I'm not sure as of now. It is the one that screws into the oil screen housing. It also has a wrap around finned heat sinc that wraps around the filter.
I will chk the 2 blast tubes tomoro along w checking for exhaust leaks as described. And the guage looks original. Solid green arc up to the red line which indicates either 220 or 240. Don't remember. I'll try to figure out how to test the guage as well. Thanks everyone. I appreciate all the suggestions and the help.

[Puddlejumper]

Thanks for the tip Aryana. I will chk that out.

[cessna170bdriver]

... Is there a reason straight 50w is recommended over 20/50 multi-viscosity?...

As was mentioned earlier, TCM allows a max oil temp of 240 with straight 50W oil, whereas it's only 225 with other/multiple viscosity oil. I run the Phillips 20W50 in mine, cradle to grave, as recommended by ECI, my cylinder manufacturer. After looking at these airplanes for nearly 35 years, the most common reason I've seen for high oil temps is poorly fitting and/or poorly sealed baffling. Since putting all new baffling (from the company now called Airforms) on my O-300A at overhaul in 2006 my oil temp topped out around 210-215 during extended climbs on the hottest days when I lived out west (100+ degrees F).

[GAHorn]

... Is there a reason straight 50w is recommended over 20/50 multi-viscosity?
.... I'll try to figure out how to test the guage as well. Thanks everyone. I appreciate all the suggestions and the help.

Because that's the oil specified in the Type certificate for the increased allowable oil temp.

Plunge the bulb into boiling water and confirm it reads 212F at sea level. (Good luck getting a reading that accurate w/the original gauge.)

A simpler method is to go to the Academy or BBQ store... buy a long-probe cooking thermometer (14" or longer)... confirm it is accurate with boiling water... then fly your airplane until the oil is hot, land and without allowing any cooling, plunge the BBQ thermometer down the oil-dip-stick tube to measure current oil temp...and compare to cockpit gauge.

[Puddlejumper]

Thanks to all the respondents to my questions. I tested the oil temp guage using what I think was an ingenious method. In case anyone needs to test theirs, here is what we did. I took an electric turkey fryer (small, light, simple. I think even a small electric fryer would work) and bought a $1.95 quart of vegetable oil which I heated up to 250°. I used 2 different probe thermometers that came w the fryer to test the temp. We took the oil probe out of the housing (and of course drained the oil) and it hung down about a foot.

Here's the good part... trying to figure out what to put 250° oil in to get it up in the engine compartment, my flyin buddy said " hey, that yeti cup you got your coffee in would work perfect"! He was right! I dumped the coffee, filled the yeti w hot oil, and it slid right up in there perfectly where I could put the prob in the hot oil. He later said I should take pictures and send to yeti for advertisement.

We monitored the guage at 250°, 240°, 225° and 200°. The guage needle actually completely covered the red line at 220°. Was nearly totally to the right of the red line at 225°. And had black area between the needle and red line at 245°so I now know I can fly totally in the red and still be ok. Does anyone have any suggestions where I can find a new guage assembly w bulb? .
We also checked exhaust system for leaks, checked baffling, and made sure cool air blast tubes were positioned properly. Thanks again for everyone's help.

[gfeher]

If you do buy a Rochester gauge like the one Arash identified, don't forget to test it/check its accuracy before you install it. These gauges are not the most accurate gauges in the world even when new. So it's good to know how it reads before you install it. A check at different temps like you did with your current gauge would be perfect and useful for the future.