oil temp difference between engines (twin)
 

Hi folks

is 20 C oil temp difference between engines on twin is normal ? of course both within the limits

Regards

Can be quite normal, sometimes one engine is just alot newer.

Trend sheet is always handy in tracking these things

A 20 degree difference in oil temperature? Or a 20 difference in indicated oil temperature? Try swapping the sensors and see if the higher temperature follows the sensor. If so, change the sensor. If not, check the thermostats on the oil cooler circuits. An engine running 20 degrees hotter than another due to the engine itself is highly unlikely in my experience.

If it's in the green it's a good machine ! If you fly the same aircraft all the time though, you should have a good idea of where the needles usually sit though. Just monitor frequently.

In general, yes. For some models it is a "feature" of the aircraft.

If you flew two singles and the oil temp indications were 20 deg different you'd probably never even notice.

Even with the oil temps being within limits, if there is a change in trend over time it should be brought to the attention of a mechanic. If the 20deg temperature difference is normal for that aircraft, I would not worry about it.

Leaks in the oil cooler ducting downstream of the blower or partial blockage of same can be a cause. As Gulli says, the trend may tell you, but if its been there since an engine change it's still worthwhile having a check, duct leak, rag left in duct. Can't say I've ever seen such a discrepancy, but it's stretching the memory.

Theoretically I guess it's possible if the oil cooler bypass are out of sync but within the operating limits. My type specs were thermostat full open <57+-3°C, fully closed >67+-1°C, open >40PSID.

Exactly...

Try flying with the ball in the centre. :):):)

I have seen an engine removed because it was running higher engine oil temp than the other engine, turned out it was the other engine running cooler...........

Has this suddenly happened? Does one engine appear to warm-up quicker? Is the Delta-T consistent at all stages of flight? ? Pressures OK? What temperatures are indicated when the engines are cold?

If this was a Medical Forum we'd probably be advising you to talk to your GP/doctor/physician, not just other patients.. Talk it over with your Continued Airworthiness guy or Mechanic/Engineer; that won't cost you a penny. They can advise the most cost-effective troubleshooting if they are concerned about it; for instance transposing the indicators and/or the temp transmitters.

Check that the oil cooler fan shaft is complete. In the 135, if oil cooler fan is broken the oil temp is about 20-30deg higher.
Spin the blades and look at the fan.

How do the indications compare when the engines have cooled down completely?

Is this in all phases of flight?
This could be a cowling issue or baffles or even mixture.
We need a little more info.
How old is the airplane, how old is the wiring, the gauges, when did the engines get overhauled, is oil consumption equal etc etc etc.
In the big scheme of things, no, this doesn’t have to be a problem but it could.

Mixture? As far as I know all twin engine helicopters are turbine engine powered. Not sure how the mixture theory applies there.

You forgot the Kamov Ka-26 :)

skadi

Yeah my mistake.
I missed that this thread was in the rotor section
Was thinking piston Twin fixed wing…
Disregard that last transmission.

Prrune shame...worse than that stuck mike ! :)

to all of you , thanks for advice , sensor pin cleaning did help , all normal .

Regards