Low oil Temperature

[Guest]

7 hours ago, takair said:

Clarence

Did you ever solve this?  I have been noticing that my oil temp has been drifting lower.  It used to hold 180f, but now tends toward 160.  Today, with about 45f OAT, it would drift between about 155 and 170.  Wonder if I have a sticky vernatherm?

We have replaced the oil vernatherm valve and still have the same issue with cool oil temperature.

Clarence

[kmyfm20s]

My first guess is the vernatham is stuck open and allowing the oil to free flow. I would verify that it is able to open and close properly with temperature and that there is no mechanical restriction preventing it from opening and closing when installed. I would also check the thermocouple for accuracy and if accurate try relocating it to one of the other location available for installation. Lastly but most improbable is to check that oil is actually flowing over the thermocoupler and not getting a passive reading from a stagnant pool of oil. 

[markejackson02]

My suggestion is to move to South Texas where low oil temperatures are never an issue.

[Guest]

On August 11, 2017 at 5:49 AM, kmyfm20s said:

My first guess is the vernatham is stuck open and allowing the oil to free flow. I would verify that it is able to open and close properly with temperature and that there is no mechanical restriction preventing it from opening and closing when installed. I would also check the thermocouple for accuracy and if accurate try relocating it to one of the other location available for installation. Lastly but most improbable is to check that oil is actually flowing over the thermocoupler and not getting a passive reading from a stagnant pool of oil. 

Two different vernatherm valves have been tried, the engine has two different oil temperature systems. Oil temp still follows OAT.

Clarence

[Guest]

On August 11, 2017 at 10:01 AM, markejackson02 said:

My suggestion is to move to South Texas where low oil temperatures are never an issue.

Thanks for the offer, however shovelling some snow is preferable to sweating all year.

Clarence

[rxo188]

So, from what I remember studying aircraft systems, doesn't an oil cooler have a thermostat-like device that bypasses the cooler until a certain operating temperature is reached? My 1987J model oil temperature runs low too. Normal summer months it's barely showing up on the gauge which starts at 150f. This is verified by the digital readout on the JPI instrument that normally operates in the 130s when I fly in single digit Celsius OAT. On hot days it might crack 150. I've ran it like this for 900 hours and I have no compression, consumption or contamination issues. I thought about partially blocking off some of the cooler for the winter. Has anyone actually blocked the cooler and experimented?

[carusoam]

That would be the vernatherm That is being discussed above...

Thermostatic valve for oil cooler...

Tested by boiling in water.

RXO, It would help if you could put an approximate location in your data under your avatar...

Some people block off a portion of their oil cooler.  The IO550 has a winterization plate. 

Data regarding your plane will help as well...

Best regards,

-a-

[Yetti]

On 8/12/2017 at 12:09 PM, M20Doc said:

Thanks for the offer, however shovelling some snow is preferable to sweating all year.

Clarence

Don't have to shovel humidity

[Guest]

7 hours ago, Yetti said:

Don't have to shovel humidity

We get plenty of that in summertime.

Clarence

[cbarry]

One other thing to check:  You very well could have a grounding issue on the temp gauge.

[jlunseth]

On 3/22/2017 at 6:34 PM, M20Doc said:

I'm having issues with a J model which has low oil temperature.  We installed a newly overhauled engine last summer with all new baffle tapes, sealed every conceivable gap in the metal baffle tapes, all engine accessories were overhauled.  The engine is operated at normal cruise power setting with CHT values of 300+/- and the oil temps on the G4 between 125-150.

Lycoming say it sounds normal for OAT in the 20's to 30's and suggested a call to Weber Aircraft, who were equally stumped.

Any ideas?

Clarence

My thought is the one mentioned earlier - that the engine runs too cool to heat the oil up much.  The giveaway is CHTs in the 300 range.  Just to be clear, I take it that means what it says, the CHTs are around 300 and not up around 350-380.  If your OATs are in the 20-30 range, not of it seems abnormal to me, except you might have some trouble when winter gets really cold.  I have a K, there is no minimum redline OT, but there are warnings in the POH to keep OT above 100.  Our problem is different though, we need oil thin and warm enough to cool the turbo bearings.  The oil cooler block several people have mentioned has always been the best solution for me, my A&P made up one from pieces of open cell foam taped together which is then stuffed in the cooler.  Works good, and you actuallly get some heat off the heater to keep the cabin warm during the winter.  Unless of course you fly in the flight levels and the OAT is -50 F.  That is a different story.  

I just don't think you have anything wrong except a very cool running engine.