Oil level for C172SP?

nj-pilot

nj-pilot

Pre-takeoff checklist
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josh_me
Hello - POH says min 5 quarts and max 8 quarts. I generally like to have around 6 to 6.5 quarts when I depart. I'm a renter. Airplane was down to ~5.5 quarts or so. I asked for another quart to fill to 6.5, and they told me that they do not like to add more oil until it hits 5 quarts. Seems a little risky. Is this the norm?
 
You were fine. It depends on the length of flight, but 6 is what I like to see in a 172.
 
The POH says minimum 5 quarts, and you're over that. Good.

It also probably says to fill to 8 quarts for extended cross-countries.

I'd ask what the burn rate is, and if the level isn't projected to go below 5 quarts during the flight, that's fine. If it's burning rapidly (like a quart an hour), I'd take a different plane.

I generally like at least 6 in one of these, but many of them will just make a mess out the vent if you fill them too much over that.
 
You are fine. The 5 qt. limit is minimum for take-off. Basically, Lycoming and Cessna believe that at 5 qt., you'll run out of fuel before you run low of oil. The reality is that most of the oil in the pan is for cooling, not lubrication. As little as a quart or two will lubricate the engine. I believe (someone check me on this), the engine is actually rated to run all the way down three quarts, even from a cooling perspective.

Also note that the engine actually has an additional quart you don't see on the stick, as the stick is calibrated for no oil filter, and all IO-360-L2A have oil filters. That doesn't help for the level, as you need the extra oil to fill the filter. However, that extra oil does increase the cooling capacity available.

I personally use 6 as a minimum as well, but there's nothing that is really wrong with using the book numbers. Also, even the book indicates that most of the last quart, the eight quart, would be wasted out the tailpipe if present. That last quart is really only there for long, hot trips on a tired, oil-burning motor.
 
arnoha said:
You are fine. The 5 qt. limit is minimum for take-off. Basically, Lycoming and Cessna believe that at 5 qt., you'll run out of fuel before you run low of oil. The reality is that most of the oil in the pan is for cooling, not lubrication. As little as a quart or two will lubricate the engine.
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He's right. That is good to take into consideration for long cross countries but if you're over the minimum, you're within range. You might also want to take note that if you checked the oil level when the engine (and oil) was cold, that oil will read lower than it will when it's warm since the heat causes it to expand. I don't know by how much it expands, but it is noticeable.
 
Normally, anything over 6 quarts blows out the vent anyway.
 
I keep mine between 6 and 7. But they maintain the plane. Do it their way.
 
nj-pilot said:
Hello - POH says min 5 quarts and max 8 quarts. I generally like to have around 6 to 6.5 quarts when I depart. I'm a renter. Airplane was down to ~5.5 quarts or so. I asked for another quart to fill to 6.5, and they told me that they do not like to add more oil until it hits 5 quarts. Seems a little risky. Is this the norm?
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They would know the plane best. In my 172 I wait till it gets to 5, and throw in another quart... rinse repeat. More than 6 and it blows out.
 
Yup, planes have the place they like their oil level, over that it just ends up on the belly.

That said you should still have a spare qt and a funnel in the back
 
James331 said:
Yup, planes have the place they like their oil level, over that it just ends up on the belly.

That said you should still have a spare qt and a funnel in the back
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Anything over 6.5 for me. I'll fill it to 6.5-7 before starting a long cross country full well knowing I'll lose some, though. Otherwise she don't burn much.
 
rachelk.tailwinds said:
He's right. That is good to take into consideration for long cross countries but if you're over the minimum, you're within range. You might also want to take note that if you checked the oil level when the engine (and oil) was cold, that oil will read lower than it will when it's warm since the heat causes it to expand. I don't know by how much it expands, but it is noticeable.
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I was under the impression that a warm engine reads lower on the dipstick compared to a cold engine since all of the oil in the cold engine has drained out of the block and back into the pan.
 
Lachlan said:
I was under the impression that a warm engine reads lower on the dipstick compared to a cold engine since all of the oil in the cold engine has drained out of the block and back into the pan.
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I don't know about you, but when mine is warm, most of the dickstip is covered from splashing.
 
mkosmo said:
I don't know about you, but when mine is warm, most of the dickstip is covered from splashing.
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It's ok to pull the dipstick all the way out and wipe it before reinserting it to get an accurate measurement. :wink2:
 
Lachlan said:
It's ok to pull the dipstick all the way out and wipe it before reinserting it to get an accurate measurement. :wink2:
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Okay, so, I've done that... and getting it to feed down the middle and not scrape oil off a side still alludes me to this day in the airplane. It's not like my truck with a guide and a narrow fill tube that's not large enough around to take oil splashing up ;)
 
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