High oil temperatures

[lithium366]

After an overhaul I have 220-230 oil temp. Removed oil filter adapter and tested brand new vernatherm - doesn’t fully close when boiled together with oil filter adapter. Same with old vernatherm that worked perfectly before overhaul (it has a nice ring indentation  indicating it worked previously). Both open up a bit less than 1/4 inch. Same with another brand new oil filter adapter. Now I am scratching my head, 2 vernatherm, 2 oil filter adapters - what’s wrong? There is also one washer installed between vernatherm and oil filter adapter

Q: is washer between vernatherm and oil filter adapter required? Removal would solve the issue

 

Q: any potential gotchas testing vernatherm in water vs oil? Curious if oil provides some additional qualities that help vernatherm open up? 

Edited August 3 by lithium366

[Fritz1]

Water boils at 212F, oil gets hotter, something else may have changed, check the oil temp sensor, make sure oil cooler is clean and unobstructed, make sure cowl baffling seals tight, no holes with light shining through

[lithium366]

6 minutes ago, Fritz1 said:

Water boils at 212F, oil gets hotter, something else may have changed, check the oil temp sensor, make sure oil cooler is clean and unobstructed, make sure cowl baffling seals tight, no holes with light shining through

To my knowledge vernatherm should fully open 180-190 degrees so you oil doesn’t get hot

Savvy also thinks it’s a vernatherm issue based on data they see (oil temp flat is too short when vernatherm opens up) 

Edited August 4 by lithium366

[Fritz1]

Yes, that is about what I remember, so the vernatherm is probably not the culprit since you tried two of them, baffling makes a huge difference, check temp sensor

[Fritz1]

There are steel baffles between the cylinders, verify those are installed

[lithium366]

3 minutes ago, Fritz1 said:

There are steel baffles between the cylinders, verify those are installed

Cyl temps are normal, I checked inter-cylinder baffling. I am convinced the issue is vernatherm / seating - you can see a light going thru the seat. That should be fully closed?

[MikeOH]

I've fought this issue for the nearly 7 years I've owned my F.  So, I'm REALLY interested in what you find out!  But you may be on to something with the valve not seating completely.  However, my understanding is that it seals off when HOT, which forces the oil out to the cooler.

I had the oil cooler overhauled, replaced the vernatherm, replaced the hoses to and from the cooler, new baffles...oil temp still runs 220-230 on hot days.  I've been trying to figure out how to independently verify that oil is actually flowing through the cooler.  I went so far as to buy a two channel temp probe and tried to instrument the input and output fittings of the oil cooler.  Unfortunately, that didn't really work; the probes need to be INSIDE the lines to directly measure the oil temp; no way to do that.

[PT20J]

From my notes at the Lycoming factory class:

#1 cause of excessive oil temperature is vernatherm. It should begin to expand at 150 degF and should be max expansion (>= 5/32") at 170 degF. Also check that Vernatherm doesn't have a break in the seal of the cone to the seat.

Other causes: restrictions in oil cooler hoses, blocked airflow to oil cooler, oil cooler needs overhaul due to trapped contaminants.

[MB65E]

What gasket did the pressure housing get? There are three. Mine was incorrect after I overhauled mine. IPC isnt the clearest. 
-Matt

[PT20J]

4 hours ago, lithium366 said:

Q: is washer between vernatherm and oil filter adapter required? Removal would solve the issue

IPC shows a 76510 gasket.

[lithium366]

1 hour ago, PT20J said:

From my notes at the Lycoming factory class:

#1 cause of excessive oil temperature is vernatherm. It should begin to expand at 150 degF and should be max expansion (>= 5/32") at 170 degF. Also check that Vernatherm doesn't have a break in the seal of the cone to the seat.

Other causes: restrictions in oil cooler hoses, blocked airflow to oil cooler, oil cooler needs overhaul due to trapped contaminants.

Both vernatherms I have Lycoming and Superior stamped 85 C. That’s 185F and that’s about the temperature they “mostly” closed. They continue to expand at a much slower rate until water boiling temp. It’s interesting Lycoming mentions other temps

I sent oil cooler to overhaul during engine overhaul, it’s hot to touch after flight but perharps vernatherm only partially open allowing temps to go up

[lithium366]

55 minutes ago, MB65E said:

What gasket did the pressure housing get? There are three. Mine was incorrect after I overhauled mine. IPC isnt the clearest. 
-Matt

Can you clarify what is the pressure housing gasket and how it relates to oil temp?

[MB65E]

The factory non-filter pressure screen housing, and the factory oil filter housing all have different part number gaskets. I had the original pressure screen gasket on my factory oil filter housing installation. The gasket ported the oil differently and never sent oil to the cooler. 
I maintain several airplanes that don’t have the filter housing just the old screens so I just grabbed an old pressure screen gasket. The oil filter housing gasket is different vs the P-screen. 
-Matt

[MB65E]

For reference attached pictures. 
First one PN 06B23862 is for the oil filter adaptor. 

PN 61173 is for the pressure screen only. 

If you run an oil filter and it mounted on the back of the case use PN 06B23862.

-Matt
 

Edited August 4 by MB65E

[M20F]

Overhauled engine or overhauled oil cooler?

[PT20J]

10 hours ago, lithium366 said:

Both vernatherms I have Lycoming and Superior stamped 85 C. That’s 185F and that’s about the temperature they “mostly” closed. They continue to expand at a much slower rate until water boiling temp. It’s interesting Lycoming mentions other temps

I sent oil cooler to overhaul during engine overhaul, it’s hot to touch after flight but perharps vernatherm only partially open allowing temps to go up

You could call Lycoming tech support. Since you have the old vernatherm, you could try swapping it and see if it makes a difference. 

[lithium366]

48 minutes ago, M20F said:

Overhauled engine or overhauled oil cooler?

Both

[lithium366]

8 hours ago, MB65E said:

For reference attached pictures. 
First one PN 06B23862 is for the oil filter adaptor. 

PN 61173 is for the pressure screen only. 

If you run an oil filter and it mounted on the back of the case use PN 06B23862.

-Matt
 

Oh I see, thanks for pointing out, I double checked and I have correct one

[MikeOH]

@lithium366

It looks like there are a few ways to connect the oil cooler lines to the back of the engine.  The Lycoming diagrams help but I've always wondered if mine are not hooked up correctly. I've mentioned to my A&Ps but none thought there was a problem...

Just thought I'd bring it up since you've had the issue only since the engine overhaul.

[M20F]

5 hours ago, lithium366 said:

Both

What is the max and what does it go to when you level off and lean for cruise?   Are you saying it goes to 220-230 in the climb and doesn’t reduce for cruise?

Are you still running mineral oil, total hours on overhaul, how long since last oil change?

[MikeOH]

24 minutes ago, M20F said:

What is the max and what does it go to when you level off and lean for cruise?   Are you saying it goes to 220-230 in the climb and doesn’t reduce for cruise?

Are you still running mineral oil, total hours on overhaul, how long since last oil change?

@M20F

I'm obviously not @lithium366, but my temp rises to 185 (left side of plot) for a couple of minutes, then climbs to around 230 and stays there, even after I lean for cruise:

 

[lithium366]

10 minutes ago, MikeOH said:

@M20F

I'm obviously not @lithium366, but my temp rises to 185 (left side of plot) for a couple of minutes, then climbs to around 230 and stays there, even after I lean for cruise:

 

Yep so you see that flat area at 185 - this is due to vernatherm opening and colder oil from hoses and oil cooler mix with hot oil, delaying further oil temp raise. When you have issues with vernatherm, hoses or oil cooer (like I do) that flat area is non existent or very small 

for me it looks like your vernatherm is functioning well and problem is something else

Edited August 4 by lithium366

[MikeOH]

1 minute ago, lithium366 said:

Yep so you see that flat area at 185 - this is due to vernatherm opening and colder oil from hoses and oil cooler mix with hot oil, delaying further oil temp raise. When you have issues with vernatherm, hoses or oil cooer (like I do) that flat area is non existent or very small 

@lithium366

Thanks!

Interesting, because my theory has been oil isn't circulating through my cooler for whatever reason. Your observation tends to say something is making my oil very hot; past the ability of the oil cooler.  I have good compressions and use 1 qt every 7 hours so I don't think blow-by is responsible...no idea where to look.

I did find in my research that engines without an oil cooler may have a plug, spring and plunger installed where the upper oil line ("A" in Lycoming diagrams) would attach. If only the plug and spring were removed (and the plunger left at the bottom) when the oil line was attached I could see that blocking any flow to the cooler regardless of the vernatherm.  Maybe something to check?

[Andy95W]

3 hours ago, MikeOH said:

@lithium366

It looks like there are a few ways to connect the oil cooler lines to the back of the engine.  The Lycoming diagrams help but I've always wondered if mine are not hooked up correctly. I've mentioned to my A&Ps but none thought there was a problem...

Just thought I'd bring it up since you've had the issue only since the engine overhaul.

This can be a potential cause.  I seem to recall sitting in a seminar at OSH a few years ago as this was discussed.  Hooked up wrong, the oil never fills the oil cooler, but just flows through because the oil cooler is filled mostly with air.  Worth checking.

[EricJ]

36 minutes ago, Andy95W said:

This can be a potential cause.  I seem to recall sitting in a seminar at OSH a few years ago as this was discussed.  Hooked up wrong, the oil never fills the oil cooler, but just flows through because the oil cooler is filled mostly with air.  Worth checking.

In motor racing the usual wisdom was to have both the inlet and outlet at the top, which makes an awful lot of things easier and assures that the cooler is more likely to be purged of air.    The next best way is to put the inlet at the bottom and outflow at the top.    Radiators usually go the other way because there's an independent purge and fill system and you want to maximize the likelihood that there's coolant at the bottom for the pump to draw.   For whatever reason a lot of oil coolers get set up differently, though.