Significance of Oil Temp Green?

[201er]

Since my overhaul, it seems to take a lot longer for the oil temperature to reach the low end of the green arc (150) than ever before. I think this has a lot to do with the fact that the new oil cooler is a lot more effective because the oil doesn't nearly get as hot as before at the high end either.

What I am wondering is why do we have to wait for the oil to reach 150? Is it for the sake of lubricating properties or is this just an indication that the metal in the engine is up to temp? Is it ok to takeoff before oil temp is 150 when CHTs are already approaching 300?

[Seth]

Mike-

That's a great question and I'm not sure how to answer it. I'm interested in what others have to say, also, to add to this, is 150 degrees the bottom of the green arc for all Mooney aicraft that use both Lycoming or Continental engines of all HP or is it specfiic for different engines? I need to check my POH for the number.

Not trying to steal the thread, just adding an additional fact pattern or question:

1. Is it okay to take off with oil temp below 150 if CHT's are approaching 300? (Mike)

2. Is the 150 for the oil temp to be properly lubricating or just metal pieces at that temp? (Mike)

3. Is 150 the standard for most if not all engines bottom of the green arc? (Seth)

-Seth

[jlunseth]

Is that what your POH says? The POH for my 231 says 100, and that is because warm oil is needed for the turbocharger. I find it hard to believe that an NA engine would need a significantly higher OT.

[scottfromiowa]

In recent/current issue of Plane&Pilot a Mooney driver has article called "Say When"...First item is When Should you power-up a cold engine for takeoff? He uses 100 as baseline that you SHOULD NOT do engine run up until oil is at a minimum of 100 degrees...says it's due to variety of metals in an engine and this is minimal temp...Good guideline. He also discusses the importance of digital gauges to give an ACCURATE reading on what that number is.

[Marauder]

I own an F model and getting the oil temp off the peg can be a real challenge (especially being based up north). I do wait until the needle is near the green arc but it does mean a considerable wait sometimes. Even if I pre-heat everything...

[jlunseth]

My POH says minimum 75 dF for runup. It is fairly rare, though, for the OT to be under 100 by the time I taxi down to a runup pad.

[Hank]

Here's what my Owner's Manual says about it. More or less, "no problemo," at least here along the Ohio River and points southward.

I was reminded yesterday of the simplicity of my C compared to an F. The hot start wasn't too complicated, but there was much more to monitor and adjust. Maybe it was just the particular systems, but it seemed like everything took much longer. But it climbed very nicely, and accelerated much more than I am used to on descent; then again, we had a couple of extra inches of manifold pressure, which put the airspeed halfway into the yellow very quickly. Fun, but a different experience.

'Tai'nt all the same. Follow your POH/Manual.

[jetdriven]

Mike we have the same problem as you do. Extended oil warmup times. We used to run on the ground 15 minutes to get the oil temp guage "off the white dot" as the POH says. However, in later POH's, this white dot (75 degrees F) and reference to it is gone. I wait till I see 200 on the CHT, do a runup, and depart at a 250 CHT. The oil temp moves up a few minutes after takeoff.

We also use X/C 25W50 multigrade oil, I think using the W100 on a cold day and departing with <75f oil temp could be a problem. It is like pumping molasses

According to Lycoming, if the engine can accept takeoff power without faltering, it is ready to go. I wait till I see a 250 CHT, or on a really cold day, a few minutes longer. Hope this helps.

[rbridges]

Mike we have the same problem as you do. Extended oil warmup times. We used to run on the ground 15 minutes to get the oil temp guage "off the white dot" as the POH says. However, in later POH's, this white dot and reference to it is gone. I wait till I see 200 on the CHT, do a runup, and depart at a 250 CHT. The oil temp moves up a few minutes after takeoff.

We also use X/C 25W50 multigrade oil, I think using the W100 on a cold day and departing with <75f oil temp could be a problem. It is like pumping molasses

According to Lycoming, if the engine can accept takeoff power without faltering, it is ready to go. I wait till I see a 250 CHT, or on a really cold day, a few minutes longer. Hope this helps.

I agree about the w100 being thick. it was fairly cold (high 30s) this morning and the dipstick looked like I stuck it in syrup. Made me wonder what kind of protection I was getting on a cold start. I had to idle for a while to get the oil temp above 100F. Personally, I like 105-110 before I do run up.

.

[Marauder]

Does anyone run the Aeroshel 15W50 anymore? Always have good success with it in very cold climates and still viscous enough for the warmer temps.

[N601RX]

Since my overhaul, it seems to take a lot longer for the oil temperature to reach the low end of the green arc (150) than ever before. I think this has a lot to do with the fact that the new oil cooler is a lot more effective because the oil doesn't nearly get as hot as before at the high end either.

What I am wondering is why do we have to wait for the oil to reach 150? Is it for the sake of lubricating properties or is this just an indication that the metal in the engine is up to temp? Is it ok to takeoff before oil temp is 150 when CHTs are already approaching 300?

It could be because you have a lot less blow by now that you have a new engine. When the engine is cold oil should not be going through the oil cooler if the vernatherm is working correctly.

[BigTex]

Does anyone run the Aeroshel 15W50 anymore? Always have good success with it in very cold climates and still viscous enough for the warmer temps.

Actually Aeroshell 15W50 is the only oil that Mike Busch recommends against using. If you want to understand why, Google "all about oil" and watch his webinar. If you want a multi-viscosity oil, I'd look at either Exxon Elite or X/C 20W50 with Camguard.