Oil Temp?

[TWinter]

What does your engine oil temp usually run?. Seems like mine has increased some over the past few days..Usually 198+/-. I notice this weekend it has been 200-204 on the JPI. I know there is a search button, but somebody might be able to save me so time searching threads. 1973 M20E. It's been overcast so flying has been lower altitude and 2500-2700. Temps outside in the 85-90s.

[1964-M20E]

I've seen 212 to 220 during long climbs to 10k or 12k especially during the summer and about 210 in cruise.  My cooler has been relocated to behind #4.

[AmigOne]

In my 68C one of the most consistent indications has been the oil temperature, never above 185 on climb out and 180 in cruise 

[Lood]

On my F, anything between 180 - 201 deg, depending on conditions and power settings.

[Lrn2Fly]

On my '66 E model with the standard oil cooler in front, and the JPI, I have consistent oil temps at 192-195' in cruise.  It climbs as high as 210 in an extended climb with open cowl flaps and 120 MPH indicated.  In an extended climb, if I want a cooler oil temp, I can increase the airspeed to 135 and the temps drop.   I can always close the flaps completely during cruise, after a cool down period.  My mechanic and I did quite a few things to drop the temps down from the 225' area several years ago, including baffle overhaul, new baffle seals, relocation of the spin-on oil filter further down the firewall (close to the exit of the cowl flap), and most importantly, a new gasket on the vernitherm housing.  The gasket that was in there was the wrong part and did not allow the vernitherm to seal the gap, meaning a reduced flow of oil into the cooler.  This one change made the most difference.

[TWinter]

Thanks for the input. I'll keep an eye on it. Seems to be hovering around 202-204 during a 30 minute flight just doing some light flying last night around the field..Usually I see it in the 190s max. JPI shows all CHT and EGT all normal and as usual.

[rbridges]

mine flirts with 200.  the engine monitor is set at 210.  I can touch 210 at low altitudes or during a climb.  I'll trail the flaps when it hits 210.

[Bob_Belville]

My OT runs higher than I think it should in summer but I am at a loss to what else can be done. The cooler is moved to behind cyl 4. I had it overhauled at Pacific at last annual. Vernatherm went to Pacific. New hoses to/from cooler.  I have ARI cowl and 201 style baffles which I've replaced and carefully sealed ans resealed. (I wonder about the accuracy of the OT sensor but OT matches CHT & EGT before engine start.)

 

Yet at cruise I usually have to keep the cowl flaps at least partially open to keep OT below 200. The CFs are very effective and seem to cost me only 1 or 2 knots. (CHTs are 350-375). In climb I sometimes see 220 even at 125k ias.

 

FWIW, the well respected engine builder who did the tear down for my prop strike is not concerned about the OT I see. He'd be more concerned if oil never gets warm enough.  Red line for OT is 245.

[tony]

just wondering for those that responded whose oil temps are 200+, is that just in the summer? has your oil cooler been relocated per Lasar's STC?  I'd like to know if anyone else thinks that the STC contributes to high OT in the summer. 

[Bob_Belville]

just wondering for those that responded whose oil temps are 200+, is that just in the summer? has your oil cooler been relocated per Lasar's STC?  I'd like to know if anyone else thinks that the STC contributes to high OT in the summer. 

I have the relocated cooler and OT is definitely higher when ambient is higher. The STC was accomplished before I bought this M20E so it's hard to say that move has hurt temp, I suspect not. OT in this E is very sensitive to cowl flaps, nearly 10F difference in cruise. In summer I mostly run with CF open in cruise. I close them for the normal near-red-line descent since there is a 130 k ias limit on open CF. 

[jnisley]

Normally around 185-205 but if seen as high as 220 during climb on hot days.

[ArtVandelay]

I notice mine jumps up at idle on landing (230-250F), it goes right back down if I increase the RPM

[rbridges]

I guess mine is mid pack.  I always see the people talking about <200 temps, but I'm kinda glad to see others running a little higher.

[FlyDave]

Last year in my J my oil temp started creeping up. When it finally hit an average of 215-220 dF I replaced the vernatherm and poof - right back down to 185 in cruise.

[63C]

Last year in my J my oil temp started creeping up. When it finally hit an average of 215-220 dF I replaced the vernatherm and poof - right back down to 185 in cruise.

Ditto on the Vernatherm.

[Bob_Belville]

Ditto on the Vernatherm.

Interesting. I sent the vernatherm to Pacific when I had the cooler rebuilt. They said it checked out but rebuilding the cooler did not help oil temp... we had already verified that the valve opened in hot water. Did your old valve check okay?

[FlyDave]

If I remember correctly, the person that looked at it said the face that seals against the block was slightly warn or distorted. I think they still have it and if so I'll take a picture and post it.

[63C]

Interesting. I sent the vernatherm to Pacific when I had the cooler rebuilt. They said it checked out but rebuilding the cooler did not help oil temp... we had already verified that the valve opened in hot water. Did your old valve check okay?

I should've elaborated a little. Mine ran consistently high oil temps. Pulled the cooler and had it checked and cleaned without any improvement. Pulled the hoses to replace and discovered that the tip had broken off the Vernatherm and wedged itself in the opening of the 90 degree hose end. Mystery how it ended up there.

[Mooneymite]

There's a pretty good overview at:

www.yeeles.com/Reference/Hi-Temps.pdf.

The vernatherm is often blamed, but it is a pretty simple device that primarily helps the oil to warm up faster. Once it closes, allowing the oil cooler to do its job, it really isn't a factor. If it gets stuck, engine oil will warm very slowly, or if it doesn't open flow to the cooler, oil temp may go well above limits.

[Bob_Belville]

There's a pretty good overview at:

www.yeeles.com/Reference/Hi-Temps.pdf.

The vernatherm is often blamed, but it is a pretty simple device that primarily helps the oil to warm up faster. Once it opens allowing the oil cooler to do its job, it really isn't a factor. If it gets stuck, engine oil will warm very slowly, or if it doesn't open flow to the cooler, oil temp may go well above limits.

Can it either open at the wrong temp or only partially open? I think I've exhausted most other possible culprits. It would be nice to be able to close the cowl flaps at 10,000', OAT in the 40sF, w/o the OT creeping up to 207F.

[ArtVandelay]

Can it either open at the wrong temp or only partially open? I think I've exhausted most other possible culprits. It would be nice to be able to close the cowl flaps at 10,000', OAT in the 40sF, w/o the OT creeping up to 207F.

How hard would it be to remove it, clean it, put it in boiling water to see if it works?

[Bob_Belville]

How hard would it be to remove it, clean it, put it in boiling water to see if it works?

It's kind of a PIA, but we did just that, it checked out okay. Then I shipped it to Pacific w the cooler, they checked it out, again okay. I'm grasping at straws... 

 

(If it were not for all the guys on here with oil temps staying below 200 I would be dumb and happy.

[N601RX]

It actually closes to force oil to go through the cooler. That's why if the seat is damaged it will not close off and will overheat.