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So I thought I would just ask what oil temps others are getting. Want to know for o360 models or io360 that still have the oil cooler in the nose Would really appreciate honest answers for both peak after climbing and in level cruise. Also what are conditions like OAT and what performance settings were at the time. Just looking to see where I'm at based on other similar models.

thanks in advance 

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2 hours ago, bonal said:

So I thought I would just ask what oil temps others are getting. Want to know for o360 models or io360 that still have the oil cooler in the nose Would really appreciate honest answers for both peak after climbing and in level cruise. Also what are conditions like OAT and what performance settings were at the time. Just looking to see where I'm at based on other similar models.

thanks in advance 

I put mine in "Today's Flight." The oil cooler is still in the nose, and I have the guppy mouth closure.

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21 hours ago, bonal said:

So I thought I would just ask what oil temps others are getting. Want to know for o360 models or io360 that still have the oil cooler in the nose Would really appreciate honest answers for both peak after climbing and in level cruise. Also what are conditions like OAT and what performance settings were at the time. Just looking to see where I'm at based on other similar models.

thanks in advance 

I brought my plane home from annual this morning.  Temp ran in the red (over 240) at cruise.  Temp increased to this level on climbout to 5,500 feet and stayed there the entire trip home which was an hour flight.  Outside temp was around 95 degrees, but it doesn't matter, as it nearly gets in the red in the middle of winter.  I have complained and complained and complained about the high oil temps ever since i've owned the plane which is over 8 years.  I've had two different mechanics in the past 8 years or so.  Had the engine overhauled 250 hours ago and it's the same result.  I've had the cluster gage checked, and this annual I had my mechanic install a new oil sensor.  Mechanic called it a bulb.  It made no difference.  I have a '64E with a iO 360.  I read the MAPA list quite a bit and the only thing I can conclude is the engines run hot on my model.  Most of the postings I've seen talk about the baffling being the problem.  My plane has a doghouse and it's not perfect but was reworked/parts replaced when the engine was overhauled by my mechanic.  None of it has made any difference.  My mechanic does not think the engine is really running that hot, but I'm not so sure.  If you have any findings, I'm all ears!

 

 

Edited by Kanokla
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Welcome Kanokla, I did see a reduction in temp after we installed a new vernatherm need to make some more flights to confirm how much but looks like about ten maybe twelve degrees. Interesting thread to make your first post on I'm sure folks around here would like it if you introduced yourself. When speaking with a fellow who is restoring an Ercoupe while waiting for my tire to go flat again I told him my numbers for the oil and he said I may not have a problem but I still think them a bit high. Next step will be to OH the cooler and see where that leaves me after that will just be what it is. 

Any others out there care to chime in with your numbers on the oil.

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1) the oil temp is a variable resistor that is temp dependent.

2) It is actually kinda bulb shaped...

3) They can be measured for resistance over a range of temperatures.

4) If your CHTs are in line and EGTs are in line, it is nearly expected that the OIlT is going to be in line...

5) There is an oil cooler that can be checked... the line in and the line out should be at different temps... an IR thermometer can be very helpful for this... aim and shoot while on the ground.

6) There is a valve before the oil cooler that either works properly or fails open(?) sending oil through the heat exchanger.

7) Stop on the way past the Harbor Freight tool store and pick up one of those cheap IR thermometers.

8) The issues covered here...

  • The issue is either real or not real.
  • A sensor is either working or not working properly. Test it, prove it to work... (Clarence has given additional insight below)
  • An oil cooler valve is either working or not working. Remove and put in water and allow to heat and boil for testing.  IR thermometer can be helpful again here... test it, prove it to work. (See Clarence's post for Vernatherm and location, below)
  • oil heat exchangers are often OH'd, the fins get crushed, or the oil flow gets blocked and replacement may be a good idea. Sending it out for OH is a way to test it and proving it to work.
  • Everything in this list gets proven to be working, but the oil T is still too hot...  that could be a serious challenge...
  • Proper oil flowing through the proper channels would overheat if moving metal parts don't get lubricated properly.
  • overheating metal parts this way would show up in oil analysis and visual analysis.

A quick web search shows oil degradation occurs at or above 375°F.  Realistically it begins to be less effective as a lubricant, the hotter it gets.  The viscosity thins with temperature.  As the oil's chemistry breaks down at elevated temps, its viscosity is being altered as well.

I would want to know why I had an OilT not behaving properly.  Something I couldn't ignore...

PP thoughts only, welcome to your first public post.

Best regards,

-a-

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1 hour ago, Kanokla said:

I brought my plane home from annual this morning.  Temp ran in the red (over 240) at cruise.  Temp increased to this level on climbout to 5,500 feet and stayed there the entire trip home which was an hour flight.  Outside temp was around 95 degrees, but it doesn't matter, as it nearly gets in the red in the middle of winter.  I have complained and complained and complained about the high oil temps ever since i've owned the plane which is over 8 years.  I've had two different mechanics in the past 8 years or so.  Had the engine overhauled 250 hours ago and it's the same result.  I've had the cluster gage checked, and this annual I had my mechanic install a new oil sensor.  Mechanic called it a bulb.  It made no difference.  I have a '64E with a iO 360.  I read the MAPA list quite a bit and the only thing I can conclude is the engines run hot on my model.  Most of the postings I've seen talk about the baffling being the problem.  My plane has a doghouse and it's not perfect but was reworked/parts replaced when the engine was overhauled by my mechanic.  None of it has made any difference.  My mechanic does not think the engine is really running that hot, but I'm not so sure.  If you have any findings, I'm all ears!

 

 

The first step would be confirming the accuracy of the oil temperature gauge.  Boiling the oil temp bulb in hot water or hot oil with a thermometer should tell you if it's accurate or not. Is the new oil temp bulb the correct part number for the gauge and engine?

The vernatherm valve is installed in the oil filter housing, a worn seat or valve can cause this, or a dirty and clogged oil cooler, poor fitting or leaking baffles can cause higher engine temps as well.

Clarence

 

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Sharing this thread with the new guy is what MS is all about. For the record we did do a boiling test last oil change. And confirmed factory gauge was 19 degrees high. Since added JPI slim line digital temp gauge. My question is what is the expected difference in temperature of the oil in the screen housing and the front of the crank case where the JPI probe is placed. However I am basing my reduced oil temps on the just replaced vernatherm since the JPI has been in place for the previous 20 hours of flight done at last oil change. And the new valve is showing an improvement.

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This is why the redlines, green arcs and yellow zones, on our instruments are both device and location specific.

Actual oil temps can vary by location depending on the day.  Up by exhaust valves can get extremely hot.  Same thing in TCs where the oil does much of the cooling.  These metals are close in proximity to where the EGT is the highest...

The important thing is the aggregate temperature that is read by the ship's gauge.  Because all of the testing in the development of the airplane was done this way.  All of that proving now applies directly to the airplane you are flying...

#1 reason I like my factory built airplane... so many things are proven out in advance.  So many other things get proven every day by the large MS community and shared....

The important thing that Clarence pointed out is maintaining the conformity with the original design...  it would be bad form to accidently have the wrong sensor (part number), or worn valve/seat...

In a similar fashion moving the ship's CHT sensor from its standard location to allow for near perfect engine monitor graphs...

Best regards,

-a-

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Absolutely correct and why I still have factory bulb in its original location and the JPI in its design location at the front of the case. Another thing that is encouraging is my lovely co pilot (wife) who has a better site line to the factory gauge commented that the needle used to be just touching the red line and last flight she noted it was clearly in the green so I think that's progress. But would still appreciate other folks sharing what temps they are seeing.

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In my C with the oil cooler in the nose and guppy mouth closure, flying 1300-1400 CDT yesterday, I did a Vy climb to 7500 msl to reach cool air. In the climb, my factory Oil Temp was near the top of the green line (I leaned over to get a good view); once I leveled off and set 22" / 2400, the needle moved towards lower temps. Note that there is a needle-width gap between the green stripe and the red line, and my Oil Temp needle did not edge into the gap.

Sorry, I didn't think to take a picture . . . . Maybe next time? OAT on the ground was well into the 90s; at 7500, it was 68°, or 36° above standard.

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Mine seems to sit right at about 180° whether climbing, cruise, whatever... It has the oil cooler in the nose. I do have to adjust climb to help keep my CHT temp down (just the single monitor on the #3 cylinder), but the oil temp seems to stay fairly constant.

The one thing I do notice is that at full power and 2,700 rpm on take off I see my oil pressure right in the middle of the green arc, but once everything is all the way warmed up and I dial the rpm's back the oil pressure sits at the bottom of the green arc.

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Well I guess our Snoopy just runs hot on the oil. pressure is perfect middle of the green even when fully hot. and cylinder #3 levels out at about 360 to 370 in cruise. will be looking into Cooler next.

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5 minutes ago, bonal said:

Well I guess our Snoopy just runs hot on the oil. pressure is perfect middle of the green even when fully hot. and cylinder #3 levels out at about 360 to 370 in cruise. will be looking into Cooler next.

If we could find the combination of my temp staying where it is and your pressure where it is that would be perfect.....

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  • 2 weeks later...

Today at Oshkosh I went to an interesting forum called "Lycoming Engine FAQs".  The guy (Lycoming Factory Rep) mentioned something that made me think of this thread.

If the oil cooler is not completely filled with oil vertically before installation, an air bubble can be in place in the coooler that never leaves the system (hot oil flows in the top and cold oil is pulled out the bottom).   With an air bubble, that part of the oil cooler never sees any oil, which effectively teduces the surface area by that amount.

Thought this could explain some of the high oil temperature were hearing about.

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If the oil cooler is relocated and installed vertically, the oil circuit should port the hot oil in the bottom of the cooler, not the top. The engine return should be on the top.  There will be no air bubble.  

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On July 28, 2017 at 0:05 AM, Andy95W said:

Today at Oshkosh I went to an interesting forum called "Lycoming Engine FAQs".  The guy (Lycoming Factory Rep) mentioned something that made me think of this thread.

If the oil cooler is not completely filled with oil vertically before installation, an air bubble can be in place in the coooler that never leaves the system (hot oil flows in the top and cold oil is pulled out the bottom).   With an air bubble, that part of the oil cooler never sees any oil, which effectively teduces the surface area by that amount.

Thought this could explain some of the high oil temperature were hearing about.

Andy,

Very interesting thoughts about flow through the cooler.  It makes me wonder how the oil cooler in a C172 bleeds air out? Cessna provides a drain cap on a "Tee" fitting at the cooler which is drained at every oil change, so it has the potential to be air locked at every oil change, yet it doesn't seem to happen.

Clarence

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On July 27, 2017 at 9:05 PM, Andy95W said:

Today at Oshkosh I went to an interesting forum called "Lycoming Engine FAQs".  The guy (Lycoming Factory Rep) mentioned something that made me think of this thread.

If the oil cooler is not completely filled with oil vertically before installation, an air bubble can be in place in the coooler that never leaves the system (hot oil flows in the top and cold oil is pulled out the bottom).   With an air bubble, that part of the oil cooler never sees any oil, which effectively teduces the surface area by that amount.

Thought this could explain some of the high oil temperature were hearing about.

I guess it would depend on how big the air bubble was. If so could some inverted flight clear up the problem ...kidding 

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4 hours ago, M20Doc said:

Andy,

Very interesting thoughts about flow through the cooler.  It makes me wonder how the oil cooler in a C172 bleeds air out? Cessna provides a drain cap on a "Tee" fitting at the cooler which is drained at every oil change, so it has the potential to be air locked at every oil change, yet it doesn't seem to happen.

Clarence

That's a great point- if I'd thought of it, I would have asked the Lycoming guy.  

On the vintage Mooneys, where (if I remember correctly) the hot oil goes in the upper fitting and the cold oil is pulled out the lower fitting, his idea makes sense.  Based on your point, though, it may not make much difference.  It makes me wonder how the hot/ cold oil flows in the 172's oil cooler.

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  • 2 years later...

Reviving this old thread...because it's relevant to my issue and I didn't find anything more recent.

Did anyone either prove, or disprove, the "air bubble in the oil cooler" possibility?  I ask because our E, with about 200 ours on a factory 0-time IO360 engine, has consistently high oil temps.  230-240 in cruise, at high cool altitudes, isn't uncommon.  I have both the factory gauge and a JPI EDM-700 and they confirm the high temps, so it's not a gauge issue.  The oil cooler is in the nose and not obstructed, but I see no heat shield above it (as I've seen on other photos, while researching this).  Is that plate, in some photos, really a heat shield?   

My mechanic changed out the vernatherm, but that didn't seem to improve things.  So, I turn to the possibility of an oil cooler flush or the bubble idea.  Has anyone found a plugged/clogged oil cooler?  That seems unlikely, but I'm open to experiences and ideas.

And, if it helps...when I open the cowl flaps in cruise, the oil temp drops closer to (or into) the green.  So, I'm suspicious of an airflow or cooler efficiency issue.

Thanks much,

Ross

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