oil levels

i check my oil two ways. 1) i crank the car after its been sitting all night and let it warm up to operating temperature, usaually take a good 10 minutes, turn the car off and check the oil. the other way 2) i drive the car at normal operating temperature, park it, turn it off and check the oil. both ways i check it the engine is at operating temp and the car is turned off. but when i check it the first way, without driving it, the oil level is always higher than when i check it after its been driven.
my question is why is this and is one way of checking it better than the other. thanks.

 

This is how I check my oil level:

From cold start, run the engine for 10 minutes, until the oil temp gauge move up. Keep the engine running, and check the dip. I don't have confident reading the level with the engine shut.

 

I always will: (i) actually drive my car, (ii) try to vary the RPMs, (iii) allow the oil temperature to reach the proper recommended, indicated operating temperature, (iii) pull-over in a parking lot, side-street, etc, (iv) shut my car off and (v) immediately check my oil level. Although, the Ferrari Owner's Manual does not specifically specify that the car must be driven, empirically I would think that it would give you a more "realistic" and accurate reading. Also, the Owner's Manual specifically states to shut the engine off.

To F1VTEC, don't you worry that checking the level while the engine is running (i.e., the scavenger and dry sump oil pumps are operating) will give you an artificially high oil level? While I don't take everything written in the Owner's Manual as a Fiat, and I am certainly NOT an expert, I would think this could be a problem.

 

Oh, one more thing. With regards to why the oil levels can very between just letting the car idle (or "tick-over" as Ferrari sometimes calls it) and actually driving it may have to due with the oil being more evenly distributed throughout the engine, oil pan and oil sump in a "real world" manner as the RPMs vary, the car turns, leans, bounces, etc.. Also, there may also be some very slight degree of aeration of the oil in the pan and oil tank. In sum, there are probably a multitude of factors which contribute to this phenomenon. Playing "Devil's Advocate", perhaps just allowing it to idle and then checking the oil level may be the superior method, as the oil won't be sloshed-around in the oil sump. The Ferrari Owner's Manual specifically states to "let the car idle", not to drive it. As I recall, the oil system holds a total of 9.5 liters and the difference between the minimum and maximum levels on the dip stick represents 2 liters. I'm sure Ferrari recognizes this potential problem and has built-in a wide safety margin.

I said before, I drive my car and then check the oil level but, I'm NO expert!!! Perhaps, the resident "oil expert", Dr. Ali Hass, would like to contribute.

 

Now that Rifledriver is back, maybe he can chime in....

Brian?

Mike in Kuwait

 

Oh, one more thing. With regards to why the oil levels can very between just letting the car idle (or "tick-over" as Ferrari sometimes calls it) and actually driving it may have to due with the oil being more evenly distributed throughout the engine, oil pan and oil sump in a "real world" manner as the RPMs vary, the car turns, leans, bounces, etc.. Also, there may also be some very slight degree of aeration of the oil in the pan and oil tank. In sum, there are probably a multitude of factors which contribute to this phenomenon. Playing "Devil's Advocate", perhaps just allowing it to idle and then checking the oil level may be the superior method, as the oil won't be sloshed-around in the oil sump. The Ferrari Owner's Manual specifically states to "let the car idle", not to drive it. As I recall, the oil system holds a total of 9.5 liters and the difference between the minimum and maximum levels on the dip stick represents 2 liters. I'm sure Ferrari recognizes this potential problem and has built-in a wide safety margin.

I said before, I drive my car and then check the oil level but, I'm NO expert!!! Perhaps, the resident "oil expert", Dr. Ali Hass, would like to contribute.

 

How big is the difference between the two measurement methods?

 

Hmmm. It could be a problem. But based on my experience with my own F355, I found this to be way to get the most consistent reading. Or perhaps it's due to my car doesn't use oil at all. Like you, I am no expert.

 

half way up the stick between max and min, for the no driving method. and just below or right at the min mark with the driving method. big difference.

 

Seems correct----Would seem you get the most accurate reading as Scott described....

 

Why did my second post, re-post? I didn't do it. Strange, this has happened to me twice already.

 

Wow, that is a pretty big difference, about a quart based on the owner's manual reading of the markings on the stick. I would believe the most accurate reading is the one after driving. But I have no way to confirm that. My only conclusion is what method are the majority of users likely to use when measuring? If one is supposed to only measure without driving, then the OM would likely make mention of that.