Add Oil After End of Flight or Before Start?

[201er]

I wonder if it makes any difference whether to add oil (when needed) after a flight or before the next one? Generally I've just been following whatever is more convenient but opting to do it after a flight in case I'm in more of a hurry to leave. Does it make any difference to the engine? Does it mix better in a hot engine? Or is it better to immediately run it after adding to get it flowing?

[Dale]

You know it's weird.  I just had my oil changed by a MSC last week.  I ask them to add some camguard to the oil.  They changed the oil in the morning and I was picking up the plane that afternoon.  When I came out to get the plane they told me I had to wait for a few minutes for them to add the camguard to the oil.  I ask them why they didn't do it in the morning after they changed the oil.  They mechanic told me it was best to add the camguard right before you start the engine, so it would properly mix with the other oil in the plane and not to add it and let it sit for even a couple of hours without running the plane and bringing up the oil temperatures in the engine.  I didn't think much about this until I saw your post.   I know wonder if this would apply to putting in fresh oil.  Camguard is an additive so maybe that is the real difference.  I would be interested in what others say about this also.

[Piloto]

If you read the oil level just after shutdown it will indicate about 1/2 quart lower than if you read it one week later. It takes about a week for all the oil in the upper part of the engine to drain down. If you fill the oil in a hot engine you may end up overfilling.

 

José

[jetdriven]

I dont think it matters. Oil is oil, and temperaturw in this case does not matter.  What Jose says rings true, for single weight oils.  Ours takes several days to all drain back. Aeroshell 15W50 drains back in a matter of minutes, in a couple hours the oil level is back to the true reading.  Makes you wonder what is left ot protect your cam.

Mix MMO right before flying, however. It contains a solvent which could evaporate before begin ran in your engine.

[jlunseth]

I add just before flight.  In my 231 the oil after a long flight will be down somewhat more than what Jose posted, between a half quart and a quart.  Can take a couple of days to stabilize at a level.  Don't want to put too much in, it just blows right out.

[PTK]

I also add my Aeroshell 15W50 before flight. I feel the oil level is much more accurate then.

[fantom]

Quote: Dale

When I came out to get the plane they told me I had to wait for a few minutes for them to add the camguard to the oil.  I ask them why they didn't do it in the morning after they changed the oil.  They mechanic told me it was best to add the camguard right before you start the engine, so it would properly mix with the other oil in the plane and not to add it and let it sit for even a couple of hours without running the plane and bringing up the oil temperatures in the engine. 

I suspect the guys at Premier (?) just had to run out and buy some Camguard, Dale.

When I asked Camguard at Sun&Fun, maybe 4 years age, they said to add mid oil change. That's what I've been doing ever since.

[Shadrach]

Quote: 201er

I wonder if it makes any difference whether to add oil (when needed) after a flight or before the next one? Generally I've just been following whatever is more convenient but opting to do it after a flight in case I'm in more of a hurry to leave. Does it make any difference to the engine? Does it mix better in a hot engine? Or is it better to immediately run it after adding to get it flowing?

How many Angels can sit on the head of a pin???

[Hank]

Quote: Shadrach

How many Angels can sit on the head of a pin???

[PTK]

Quote: Shadrach

[201er]

So let me see if I understood this correctly. If you fly rich of peak on a multi viscosity aeroshell oil, you should add the oil after your flight. But if you fly lean of peak and retract your gear only when no more runway left behind and use phillips with cam guard, then you should add it before the flight. What am I missing?

[PTK]

Quote: 201er

So let me see if I understood this correctly. If you fly rich of peak on a multi viscosity aeroshell oil, you should add the oil after your flight. But if you fly lean of peak and retract your gear only when no more runway left behind and use phillips with cam guard, then you should add it before the flight. What am I missing?

[Seth]

Quote: 201er

So let me see if I understood this correctly. If you fly rich of peak on a multi viscosity aeroshell oil, you should add the oil after your flight. But if you fly lean of peak and retract your gear only when no more runway left behind and use phillips with cam guard, then you should add it before the flight. What am I missing?

[N601RX]

The thermal expansion of oil is around 10% for the temperature delta that the oil would see on a cool night and inflight. At the same time the aluminum sump is going to get slightly bigger due to the thermal expansion of aluminum. Taking both of these into consideration it looks like the oil level could increase by around 1/2 quart when hot.

[1TJ]

Quote: Dale

You know it's weird.  I just had my oil changed by a MSC last week.  I ask them to add some camguard to the oil.  They changed the oil in the morning and I was picking up the plane that afternoon.  When I came out to get the plane they told me I had to wait for a few minutes for them to add the camguard to the oil.  I ask them why they didn't do it in the morning after they changed the oil.  They mechanic told me it was best to add the camguard right before you start the engine, so it would properly mix with the other oil in the plane and not to add it and let it sit for even a couple of hours without running the plane and bringing up the oil temperatures in the engine.  I didn't think much about this until I saw your post.   I know wonder if this would apply to putting in fresh oil.  Camguard is an additive so maybe that is the real difference.  I would be interested in what others say about this also.

[MARZ]

All I know is that I warm the oil up before putting it in - pours faster that way. 

And I prefer colder fuel to warmer when delivered - you get more in a gallon that way.

[Seth]

Quote: maropers

All I know is that I warm the oil up before putting it in - pours faster that way. 

And I prefer colder fuel to warmer when delivered - you get more in a gallon that way.

[OR75]

I am really not sure it makes a difference but ... I open the oil cap to let the water vapor evaporate after landing.

For some reason, i like the idea of not letting the water vapor condensate in the oil sump.  

Again, I have NO data.   

[Shadrach]

Quote: 1TJ

 It makes no difference if you add Camguard first or last. What does matter is that you run the engine after changing the oil to check for leaks and distribute the Camguard.  

Ed

Edward Kollin - Technical Director - Aircraft Specialties Lubricants

 

[1TJ]

Quote: 201er

I wonder if it makes any difference whether to add oil (when needed) after a flight or before the next one? Generally I've just been following whatever is more convenient but opting to do it after a flight in case I'm in more of a hurry to leave. Does it make any difference to the engine? Does it mix better in a hot engine? Or is it better to immediately run it after adding to get it flowing?

[Gone]

Quote: 201er

So let me see if I understood this correctly. If you fly rich of peak on a multi viscosity aeroshell oil, you should add the oil after your flight. But if you fly lean of peak and retract your gear only when no more runway left behind and use phillips with cam guard, then you should add it before the flight. What am I missing?

[201er]

Quote: 1TJ

You get a more accurate reading of the oil level if you measure it after sitting (in a given spot). However, there is no chemical or mechanical difference when you add the makeup oil.

Ed

Edward Kollin - Technical Director - Aircraft Specialties Lubricants

[Mooney_Allegro]

I don't know which is better..adding oil before or after a flight. I usually add after a flight so I'm ready the next flight.  If I'm in a hurry, I'll wait until the next flight.  I use Exxon Elite 20W-50 and don't use additives.  I buy oil from EliteEtc.com(free shipping).  I keep the oil level at 6 quarts, but for extended flights, fill it to 7.  I don't normally open up the oil cap to let out the steam after flying, but after reading one of the above posts, it sounds logical that it would help with condensation/moisture in the oil/engine.  

[jbs007]

Regardless of tempurature or time, what matters is most is the amount of oil in the aircraft while its running.  That is why I add my oil in flight.  If the oil pressure causes spewing, just climb higher, trim the aircraft up for Vy and be quick...

[triple8s]

The best method is to fly often enough so that the oil never has a chance to drain down or cool more than 10 df . If this guideline is used then you never have to worry whether you check/add oil before or after a flight because there is no difference. I however have been unable to do this as family and work keep breaking the cycle.