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Oil Temperature

Brandontwalker

By Brandontwalker
in Modern Mooney Discussion

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Brandontwalker Proficient

Brandontwalker

Posted
Posted

Good afternoon.  I am looking for some insight from my fellow Mooney fanatics.  I am new to the Mooney world and am having issues with the oil temp.  At level cruise, my oil temps are creeping above the green arc and approaching the red line (245 degrees).  I can pull the cowl flaps to half and it cools right down to normal operation range.  It has been extremely hot outside in Alabama recently, but the problem persists even at level cruise at 9,500 feet with an OAT of ~60 Degrees Fahrenheit.  I have exhausted the options I am aware of (except one which will be put into action tomorrow) and need some new ideas.

 

Thus far, we have been chasing our tails.  Cylinders 2 & 4 (same side of the engine as the oil cooler) had an exhaust gas leak which has been fixed.  My A&P and I have removed and flushed the oil cooler (flow is good and fins are straight), rebaffled the side of the engine with the oil cooler, A&P inspected and tested the vernatherm and it checked good.  Last idea is to put in a new vernatherm, which is on the way now and will be installed tomorrow.  I have seen some forum talk about potentially having cracked cylinder heads, but all compressions are over 75 and this does not seem to be the case. 

 

If the new vernatherm does not resolve the issue, then what? 

carusoam Grand Master

carusoam

Posted
Posted

The oil cooler, it's lines and the vernatherm valve can be removed (by a mechanic) for cleaning and inspection.

Using an IR thermometer is a helpful tool to see where things aren't working properly.

Some people have reported doing this in the past.

Best regards,

-a-

N201MKTurbo Grand Master

N201MKTurbo

Posted
Posted

The vernatherm forms 1/2 of the valve. The seat in the engine forms the other half, so if the vernatherm is not sealing, replacing it may not fix the problem.

You can inspect the cone on the vernatherm and the seat in the engine. You can test the vernatherm by dropping it in boiling water.

bonal Grand Master

bonal

Posted
Posted

I'm wondering what amount of labor is associated with the removal cleaning reamed and re installed.  I don't know much on this subject can someone post a photo of the assembly

carusoam Grand Master

carusoam

Posted
Posted

Simply put...

Picture a male part(vernatherm), a female part(engine), a temperature sensitive push/puller...and a by-pass

Some oil always goes around the valve through the by-pass.

More oil is allowed pass when the valve opens with temperature.

Worn valve seats usually allow flow when it is not wanted.

Stuck valves usually limit flow when it is wanted. The temp sensitive push/puller stops working

Sludge can limit the flow of oil that is allowed past the valve.

It is a good idea to check the airflow past the fins, make sure nothing is blocking the fins.

How does that work for a picture?

Best regards,

-a-

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Bob_Belville Grand Master

Bob_Belville

Posted
Posted

I'm wondering what amount of labor is associated with the removal cleaning reamed and re installed.  I don't know much on this subject can someone post a photo of the assembly

The mounting bolts (one is a nut) on my E is a little awkward to get at but probably only an hour for r&r. Our favorite engine shop, Triad, turned the piece around is a day. May not have charged my A&P as he's a pretty good customer. It only took him a few minutes I'm sure.

Cruiser Grand Master

Cruiser

Posted
Posted

what does your oil temp sensor read when you put it in a pot of hot oil?

 

Get an old pot and a hot plate, fill it with oil and use a cooking thermometer in the oil to compare temperatures with the gauge in the panel.

Releew Community Regular

Releew

Posted
Posted

What oil are you running?  I went from 15w-50 to 100w and the temperature consistently runs 30F cooler.....

 

Rick

Guest

Guest

Posted
Posted

CHT's are perfect.  Oil pressure is perfect.  Is it a correct assumption on my part that a new vernatherm will resolve any possible valve seat issues?

It would be hard to imagine oil temp at 240 and oil pressure not dropping. I would suspect that you have a gauge error problem. Remove the oil temperature bulb and place it in boiling water which will be close enough to 212 and see what your gauge reads.

Clarence

N201MKTurbo Grand Master

N201MKTurbo

Posted
Posted

FWIW

My J has an intermittent oil temp gauge. When it fails it reads high. I beleve the problem is in the plastic AMP connector behind the panel. I have an engine scanner that has a solid oil temp reading, so I don't worry about it much.

Brandontwalker Proficient

Brandontwalker

Posted
  • Author
Posted

The cooler was removed and flushed last night to no avail. The sensor is a definite possibility. Any insight as to how to remove and test the temp probe would be appreciated.

Also, I'm running 15w-50. Any other experiences with 100 weight benefits in this regard?

Guest

Guest

Posted
Posted

The cooler was removed and flushed last night to no avail. The sensor is a definite possibility. Any insight as to how to remove and test the temp probe would be appreciated.

Also, I'm running 15w-50. Any other experiences with 100 weight benefits in this regard?

The oil temperature bulb is in the oil filter adapter, disconnect the wires or cannon plug, use a wrench to remove it, usually a 7/8", reconnect the wires or cannon plug, if it's a single wire you will need to add a jumper wire to ground, place the bulb in a kettle and boil it, observe your oil temperature gauge. Water boils a 212 at sea level and 1 degree less per 1000 feet, reinstall the bulb with a new Ms35769-11 or AN900-10 gasket.

Clarence

Bob_Belville Grand Master

Bob_Belville

Posted
Posted

The oil temperature bulb is in the oil filter adapter, disconnect the wires or cannon plug, use a wrench to remove it, usually a 7/8", reconnect the wires or cannon plug, if it's a single wire you will need to add a jumper wire to ground, place the bulb in a kettle and boil it, observe your oil temperature gauge. Water boils a 212 at sea level and 1 degree less per 1000 feet, reinstall the bulb with a new Ms35769-11 or AN900-10 gasket.

Clarence

I think the slope of the curve of BP vs. Alt is a little steeper. Closer to 2 degF/1000' or perhaps Clarence, in Canada, means 1degC.

 

(@ 10k pressure altitude BP = 193.2F, 89.6C which might be important if the engines gurus who want OilT to get hot enough to boil water are right.)

Marauder Grand Master

Marauder

Posted
Posted

I think the slope of the curve of BP vs. Alt is a little steeper. Closer to 2 degF/1000' or perhaps Clarence, in Canada, means 1degC.

(@ 10k pressure altitude BP = 193.2F, 89.6C which might be important if the engines gurus who want OilT to get hot enough to boil water are right.)

Nice math...

Here is a photo of my oil temp at 10,500. The air temp and other parameters are in the picture, so you can do all the extra calculations. Looks like 191°F and 73 PSI.

4378c2a9e9fcde84d93fc30e68387fd8.jpg

Sent from my iPad using Tapatalk

  • Like 2
bonal Grand Master

bonal

Posted
Posted

Nice math...

Here is a photo of my oil temp at 10,500. The air temp and other parameters are in the picture, so you can do all the extra calculations. Looks like 191°F and 73 PSI. 4378c2a9e9fcde84d93fc30e68387fd8.jpg

Sent from my iPad using Tapatalk

Drool

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