Oil Temp Increases on 912UL

by Adam Messer in 912 / 914 Technical Questions 9 years ago

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Re: Oil Temp Increases on 912UL

by Bill Hertzel » 6 years ago

Bill Hertzel

13 1.95k 7.97k

He said it kept "...Air IN the cooler." An Air Bubble that does not get flushed out.
You want OIL in the Cooler and lots of Air on the outside.

Even if the cooler is installed above the engine, the OUT fitting still needs to be on the Top of the cooler.
The Oil flows through the cooler much slower than it does through the hoses.
You may be able to get away with the cooler being Horizontal but never Fitting Down.
Any air bubbles must be allowed to rise to the top and be flushed out the hose.

Bill Hertzel
Rotax 912is
North Ridgeville, OH, USA
Clicking the "Thank You" is Always Appreciated by Everyone.

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Re: Oil Temp Increases on 912UL

by Vattay Peter » 6 years ago

Vattay Peter

1 9 0

Rotax 912ULs 2011 600hours inTL Sting RG S4, woodcomp 3 blades hidraulic pitch constant prop
Oil tempaúeratur is 120°C (250Farenheit?) too high during climbing.
My protocol:
take off: full power on 5650Rpm, on 100feet pitch reduce 5200, on 1500feet trottle reduce for 25inHG.
oil temperature after 5 min.115-120°C !! Than reduce climbing from 6-700feet/min to 150-250feet/min
cruising: 8000-10000feet with full trotle 21inHg 5000Rpm
oil temperature 95-105°C exhoust 750°C (both side), water 90-95°C (both side) normal OK
Problem: I can not climb as intensive as the engine capacity due to the extrem high oil temperature. Sometime need 40-45 min to climb to 8-9000feet

Tried:
change all the tubes (brand new all),
ultrasonic cleaning of oil radiator, and simple washing the oil tank,
carburator overhould,
new prop woodcomp 3 blades 3000 serie
oil temperature sensor was checked OK
just after600/100 hours inspection, fresh oil and filter
My friends has the same engine in his ROKO Ul pplane he has only 80°C oil temperature,
I ask your advise what is the problem, what to do.
Thanks: Péter Vattay Hungary

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Re: Oil Temp Increases on 912UL

by Garrett Wysocki » 6 years ago

Garrett Wysocki

1 572 1.45k

Pictures of your installation would help. Have found that air leakage around the coolers can greatly effect cooling efficiency try some rubber/silicon baffling to force air thru cooler also the engine cowl outlet needs to be larger than front openings (this creates suction behind coolers) as does adjustable cowl flaps on some aircraft. My C182 cowl flaps open in taxi/climb and closed during cruise/decent.

Thank you said by: RotaxOwner Admin

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Re: Oil Temp Increases on 912UL

by udi » 6 years ago

udi

3 24 37

Is it OK to install the oil cooler above the engine?
or it has to be install below the engine?

the ROTAX manual show scheme that give this as an option, but right after that write it should be install below the engine...

what could I do to solve the high oil Temp?

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Re: Oil Temp Increases on 912UL

by Ken Ryan » 6 years ago

Ken Ryan

28 360 928

Udih,

The first line of 13.7 (page 75) of the 914 Installation Manual says this:

"On principle the oil cooler (5) has to be installed below the oil pump of the engine."

As is so often the case with Rotax manuals, this is a poor German-to-English translation, but it seems to indicate that it is "best" to install the oil cooler below the oil pump.

The next thing in the manual is this:

"CAUTION: The oil cooler has to be installed with connections upwards i.e. in
positive direction on z-axis. This will prevent an unintentional draining
of the oil cooler at longer engine stop."

This is very clear, the oil cooler "must" be installed with the fittings pointed up.

The next thing the manual states is this:

"If this position is not practical, install also the oil cooler with connections upwards
i.e. in positive direction on z-axis."

This seems to be referring to the first sentence, not to the caution statement. This reinforces the idea that the first statement actually means that it is "best" to install the oil cooler below the oil pump, but installing above the oil pump is allowed if it is not practical to install it below the oil pump.

The next thing said is this:

"CAUTION: This will prevent an unintentional draining of the oil cooler at longer
engine stop."

This is also clear. It is a repeat of the explanation as to why the fittings must be pointed up.

So it appears to me that what the manual is trying to say is this:

The oil cooler should be installed below the oil pump whenever practical. This is the best position. If it is not practical to install the oil cooler below the oil pump, it may be installed above the oil pump. Regardless of the position, it is important that the inlet and outlet fittings be pointed upwards relative to the z-axis.

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Oil Temp Increases on 912UL

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