The method I've always followed is to run the engine to operating temp, turn it off (on a level surface), and wait 10 -15 mins for the oil to settle.

 

I see both being about the same thing - you just want the oil to collect in the pan before checking to get an accurate reading. So checking cold is fine or if you have driven it, wait a bit to give the oil time to run back into the pan.

 

Both are an acceptable way to check oil, as well as checking soon after shutting the engine off and finding it at around the half-way point. If it's in the hatch marks it is acceptable, and if it's below the marks cold, it's low.

 

From my own experience with my 2013 Hatch, I get the most accurate reading when the car has sat overnight on level ground. If I try to check it when the engine has been shut off for ten minutes, there is so much residual oil in the dipstick tube that it skews the reading, sometimes making it appear you have more oil than you really do even after multiple swipes. It can even appear to be overfilled.

 

My Durango's manual says this:

"The best time to check the engine oil level is about five minutes after a fully warmed engine is shut off, or before starting the engine after it has sat overnight. Checking the oil while the vehicle is on level ground will improve the accuracy of the oil level readings."

I have trouble checking the Focus's level right after shutting down but after 10 minutes I have no trouble.

 

The main point is level car. if the car is on the typical roadside and the road is crowned and your car is tilted over to the side you will NOT get anything like an accurate reading.

As for warm, or cold, the oil should still be in the hatched marks area. Anywhere in there you are OK. I have checked my car hot (and wait a few minutes), cold (after sitting all night) and get the same levels. Seems the expansion from being hot equals the added collective oil in the crank from sitting for hours.

I agree oil does collect inside the dipstick tube, And can affect the reading. i clean the entire length of the stick before re-inserting and pulling out to check the level. that helps keep the stick free(er) of the oil in the tube body.

 

One other thing ... I find it almost impossible to read the oil level with new/fresh oil as it's so clean and transparent it's hard to see a line on the stick. I find it much easier with a couple hundred miles on it. The thing is ... you have to know how much to put in so you don't overfill or under-fill, but once you know it isn't hard to poor the correct amount in when doing an oil change.


Brian