C-85 Hot oil temp

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C-85 Hot oil temp

Post by 8319 »

My C-85 (Cessna 120) is indicating high oil temp. Oil pressure and quantity is normal. Oil temp gauge checks out OK.
Any ideas would be appreciated.
Thanks
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6643
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Re: C-85 Hot oil temp

Post by 6643 »

Expect 100 degrees over ambient. If it's hotter than that, do you have the oil screen blast tube installed? Are your baffles and baffle seals in good condition?
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Re: C-85 Hot oil temp

Post by 8319 »

Thanks John,
The answer to your questions is "yes".
I still can't figure out what is going on.
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Re: C-85 Hot oil temp

Post by 6277 »

How high is it reading? Is this a spike in temps or was it always that way? My c-85 consistently runs around 100 over OAT. With the winterization kit (block off plates and blast tube covered) it gains about 15 degrees.
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Re: C-85 Hot oil temp

Post by 8319 »

My oil temp was reading normally until the gauge went belly up. With a new gauge installed the oil temp was higher than it had been and on one very hot day (OAT was 95-100) the oil temp spiked up to 250. Since then with OAT 70-80 oil temp is running about 225 (max for the C-85). I suspected a faulty gauge, but tests showed that the new gauge is accurate. All baffles and seals are in good condition. Because the old gauge may have been giving inaccurate readings before it quit working I really have no idea what the actual oil temp was during the thirteen years I have owned the 120. The C-85 engine has 417 hours SMOH.
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Re: C-85 Hot oil temp

Post by 6863 »

This is not a pleasant thought to bring up, but you might pull your oil screen to check for metal filings. Engines making metal present high oil temps. Hate to say it.
John Kliewer

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Re: C-85 Hot oil temp

Post by 8319 »

Thanks John,
Did that, but no metal in the screen.
Also removed the oil tank and found no obstructions to oil flow through the pickup tube in the tank.
My problem: oil quantity and pressure are normal , no obvious restrictions to oil flow through the engine.
What next?
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Re: C-85 Hot oil temp

Post by 5115 »

For the expert on the forum, does the C85 has the same air-tunnel that goes from the 2 holes in front of cowling..behind the propeller. And that tunnel sends is air through a deflector that goes around the oil sump.
I believe there is a good technical article from Neil on the subject. Not all C140 have that oil sump deflector..I dont. But maybe something to look for to help cool down the oil.
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Re: C-85 Hot oil temp

Post by 5115 »

Martin Tanguay
Intl Cessna 120-140 Association - Canadian rep
C140, C-FJAR, 1946, sn:9168, O-200, ragwings
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Re: C-85 Hot oil temp

Post by 5115 »

Inter-cylinder cooling and tank baffle article. Can't seem to see it in Neil's section, so I attached it here. Just in case it can help.
Inter-cyl-oil-tank-baffle-C120-140.PDF
(204.5 KiB) Downloaded 637 times
Martin Tanguay
Intl Cessna 120-140 Association - Canadian rep
C140, C-FJAR, 1946, sn:9168, O-200, ragwings
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