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Oil Temperature runs high on climb out . . .


ibjet

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My oil temperature goes right to the edge of yellow on climb out. I am using the Dex Cool coolant. Oil is full and light color and no overheat smell to it.

 

I have noticed that when I throttle back the temprature drops off quite quickly. It does react to leveling off, but that seems to take longer than the throttling back does.

 

I'm concerned becaues we are just getting into hotter weather.

 

Is this a pretty common thing?

 

Any ideas on how to improve the oil cooling?

 

My CHT is more normal, have had it go above the middle of the green but not close to the yellow like the oil temp does.

 

Is there a way to purge the oil cooler (I had an annual done recently with an oil change, wondering if maybe there is air trapped in the oil radiator)?

 

Wow, let me just say, THIS FORUM IS AWESOME!

 

Thanks,

ET

 

 

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Hi ET,

 

The yellow on the oil temp is 230F. You'll certainly see that in many places during the summer months.  I wouldn't worry up to 245F, but if you get to 250F I would cut back level off, reduce throttle, ect... Normal cruise is usually 215F-225F depending on OAT's.

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My daily avg temps where i live are around 32-34C degrees.    I always hit 240F on the climb and cruise (5000)rpm at around 230F.    When climbing high to up high i  always do multiple step climbs to cool the temp a little bit.   Reducing cruise to 4800 or 4900 gets me  220F-225F degrees. 

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I'll have to check it out. I just got signed off for my Flight Review, I've just been doing local flying at lower power settings. I want to fly to Sun Valley, I'll cruise at higher power then. From what I have heard here, my situation is not far from normal. My ferry pilot did what one memeber here said he does: he leveled off now and then during his long climb.

 

In my Mooney I did similarly "economy climb", climbed at about 300 FPM.

 

Anyway, I'll try that cruise set up and see what temps I get.

 

Thanks guys for making me feel more normal, ha ha!

 

ET

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The Bing carbs run leaner in the mid 4k rpm range. The higher the rpm the richer the settings. The carbs run the richest at high power/fuel flow settings and this was done to help stave off detonation.

 

I'm curious what oil temps you'll see at a sustained level cruise at 5100-5200 rpm vs 4800-4900.

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Here in Georgia in the summer my oil gets a bit toasty in climb.  It's not unusual for me to see temps of 230-240° when doing sustained climbs.  If it stays below 245° I continue the climb, if it gets higher than that I will level out and let it cool a bit before continuing.  Once level the temp slowly comes down to the 210-230° range, depending on outside temps, humidity, and cruising altitude.

 

BTW I usually cruise at 5200-5400rpm, unless I'm trying to keep pace with slower airplanes.  If I'm just flying around the patch I'll use 5000rpm, but then I rarely climb above 3000ft.

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Hi Andy,

Those are all perfectly normal.

 

On the CTSW's coming in for a hose change I'm removing the return oil hose from behind the engine that makes that "S" curve and at times slows oil flow. I now turn the Banjo bolt under the engine to face to the left side between the #2 & #4 cyl. I run the hose straight out and put a 90 degree tank fitting on it. Now both intake and outlet oil hoses are straight with no flow slowing.

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I to have been changing the oil return hose during hose changes. I do it because it makes a cleaner looking installation. I'm not convinced that it makes a difference in oil temperatures. In my opinion any restriction in the hose that would keep oil in the crankcase longer allowing it to pick up more heat, would eventually lead to the crankcase being full of oil and the oil tank being empty. My analogy is a sink. If you have a sink drain that flows 3 gallons a minute and a faucet that flows 1.5 gallon per minute the sink will not fill up. If you partially block the drain reducing flow to 2 gallons a minute it still will not fill up. You can reduce the drain down ti 1.5 gallons, and everything stays static. If you reduce it to less than is coming in it will back up and overflow.

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Roger - I made that trip today and at 5100 rpm in level flight my oil temp goes to about 220.

But, I forgot to watch my oil temp when I departed Sun Valley and when I looked at it, it was at about 250!

Thou I still need to climb for mountain clearance, I throttled back to about 5000 rpm and trimmed for a more shallow climb.

So, I guess that is just something I have to learn to manage more closely.

 

My hoses were done with my recent annual, I'll have to see if I can determine that routing issue.

 

Can anyone help me with a picture of that hose rounting? 

 

New question for all: Can burping the engine aid in this issue?

 

I know I can pump about a quart of oil out of the engine back into the oil tank by burping.

 

Thanks to all, what a fantastic resourse!!!

 

ET

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Burping the engine has nothing to do with the oil temp on climb out.

 

Here are a couple of things that can help. First if you climb at too low a throttle setting that can add heat. The engine runs richer with more throttle over the 5000 so try 5200 and just shallow out the climb to keep the speed up and improve air flow through the engine.

 

Next make sure your prop pitch is set to get at least 5600-5650 rpm at WOT in level flight. If it is less than 5500 then that will build heat quick.

 

next the oil hose coming from the top right side of the oil cooler that makes a 180 degree circle and then back into the oil pump housing may have a reduced radius because of the tight bend and the heat softens the hose. I would put a spring in the hose right where the hose makes  the 180 bend to keep it wide open. I have seen this help on numerous CT's.

 

Next the oil hose that comes off the bottom of the engine and goes into the inlet side of the oil tank. If this is a CTSW and the hose snakes an "S" turn behind the engine I would re-route that to come out between the #2 & #4 cyl and put a 90 degree fitting there and make it straight. FD has done that from the factory on several CT's i have seen. I now do it at hose change.

 

It is possible that over time the oil cooler has collected some garbage and it needs to come off and get flushed out. Flush it in reverse flow first to help help dislodge anything that came from the normal flow pattern.

 

Next make sure none the 17mm coolant hoses have any reduced radius areas. This one isn't very likely, but easy enough to check.

 

 

Prop pitch and oil hose reduced ardius are the two big offenders when there is overheating.

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Also check the rubber skirt at the bottom front of the oil cooler, make sure it's pulled upward and not folded down underneath.  I noticed after every flight mine was getting tucked up under; I bent the metal support tab under the skirt up slightly, now it stays in place and my oil temps cooled about 7-10°F.  

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I took my Fiancée, Sarah, for a flight Wednesday morning and we headed north and ended up flying to the nearest part of the Grand Canyon (only 36 nm from Kingman airport). I used that opportunity to try a flatter climb out. My oil temp went to about 235. I pulled back the throttle a bit to maintain about 5200 rpm. We headed back as soon as we had a view of the Colorado River. Now I can brag that I only live about 20 minutes from the Grand Canyon, ha ha.

 

I still need to check out my hose routing and the oil cooler shrouding issue.

 

Thanks Roger and Andy and all who commented, give yourself a pat on the back!

 

ET

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Sorry, I do not have a temp guage installed. It was a bright sunny day but temps were cool. You started me wondering if there is a guage that just applies to the surface now instead of a probe.

 

I will definately check my engine out more for the issues you and Roger brought up.

 

ET

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  • 2 months later...

I have not flown much in the past several weeks, I was working on cabin lighting and re-aiming and replacing my landing light.

So, on my first night flight (took off at dusk), my oil temperature went very close to the red line! I leveled off at 5000 ft and reduced throttle to about 5,000 rpm. The temp came down to about 245. The outside temperature was probably 95 to 100. But, the odd thing is that my oil pressure is running higher than usual. It usually levels off at around 50 after the oil heats up. In this fight it was around 60 or even 65 psi.

My oil is full, still looks light on the dip stick, does not smell burned. I have about 35 hours on it since annual/oil change. I have run it on 91 octane unleaded.

My hoses are new since annual and it looks like Rex Johnson (in Tulsa) routed the new hoses the most direct way as you suggested Roger.

I ordered oil and filter today. I plan to take off the radiator and have it boiled out.

I know my ferry pilot fueled it several times on 100LL. So, I'm sure it has some lead particles in the oil.

Sorry to keep flogging this same horse, but this just is not right. Of course, the issue for me, is that I do not have any previous Rotax 912 experience to measure this against.

So, any thoughts I would be glad to hear.

QUESTION: Is this common (for oil pressure to go up the longer you go between oil changes)?

I think I must have some blockage somewhere.

I'm wondering if there is not some way to measure oil flow. Then, I would need a base line too!

I'm loving the CT and loving the night flying too (cooler, smoother, calmer for landing, easier to see other planes, but fewer of them).

OK, here's some aviator eye candy, ha ha. This jewel was in front of the huge paint hangar at the Kingman Airport the evening I went to try my night flying . . .

I asked the owner if he was interested in trading for my CT, he laughed!

 

 

 

 

 

 

 

 

 

Starship at Kingman.jpg

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You are right, the temp thing has been beat to death, and not just on this board.  Google "oil temp hot on climb out" and there are 6+ MILLION websites hits, discussing the problem.  Throw in a little Arizona, and it gets worse.  And it's not just Rotax, it's everybody.  

With your minor pressure issue, there is a small chance of obstruction, but just as likely a sensor issue, or bad connection.  You might message 207WF or Ed Cesnalis, as they both fought the battle

Until last year or so, several Starships were stored on the tarmac at Marana airport (KAVQ) 

starships.jpg

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Just 1 Starship in the picture. From the quick research I did, there are a very small number in existence. Beachcraft destroyed most of the "fleet" because they decided to shut down the program, very sad affair. I remembered the name thou, like you. Brought a smile to the owner's face! I watched him take off, it climbed out like a jet fighter!

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