Best method for dipstick reading?

[rjd2]

Hey folks-I own several older cars, and there can be a stark difference in optimal dipstick reading techniques. I just changed the oil, and have probably 5.75-6 quarts in it. It appears that 6.75 quarts is the oil capacity, but I always find that some residual oil usually remains in the head valleys, etc, and refilling the exact capacity isnt always ideal. So what's your ideal dipstick reading, and method for reading? I always feel most comfortable in a wet sump car if i know what my cold vs hot oil capacity should look like at the dipstick. thanks.

[David T]

Hey folks-I own several older cars, and there can be a stark difference in optimal dipstick reading techniques. I just changed the oil, and have probably 5.75-6 quarts in it. It appears that 6.75 quarts is the oil capacity, but I always find that some residual oil usually remains in the head valleys, etc, and refilling the exact capacity isnt always ideal. So what's your ideal dipstick reading, and method for reading? I always feel most comfortable in a wet sump car if i know what my cold vs hot oil capacity should look like at the dipstick. thanks.

With the car on flat, level ground, before you start the car in the morning so all of the oil has had a chance to drain into the crankcase, pull the stick out and wipe it off. Stick it back in, pull it out and quickly hold it level. Now check the level by looking at both sides. Ideally it should be between the low and full marks on both sides. Also examine the oil itself, it should not be black, have chunks in it, or smell bad. There should be no trace of water or water droplets anywhere on the stick. You can tell a lot more than just the level when you check the oil. The oil capacity spec is for a dry motor. When you change the oil you can never get it all out so you should not fill it to spec, you fill it to the full mark on the dipstick, whatever it takes. Then drive the car. Typically when you change the filter you go down about 1/2 to 3/4 of a quart. The next morning recheck the level and if necessary add enough oil to get 1/2 way between the full and low marks (it's always necessary). Check the level once a month or before a long trip. You should not be burning oil but you may be leaking a little, typically at the crank seal. These days you should be using a heavy truck oil with extra ZDDP, most oil for modern passenger cars does not have enough. One choice is Valvoline VR. I do not like additives, you can never know if you are adding enough or too much or how they will interact with the additive package already in the oil. Always change the oil filter when you do an oil change, the filter holds a lot of oil. Write the date and mileage on the oil filter with a marker.

[dn010]

I think this is "overthinking" but if you're really worried about it, just go by the owner's manual: "Turn off the engine and wait five minutes. Pull out the dipstick (1) wipe it clean and re-insert fully. Pull the dipstick out again and note reading. if the level falls on the knurled section, it is okay. If the level is near the bottom of the knurled section, add oil to bring it to proper level."

I go by the above personally on my old/classic cars. I run them up a bit to get the oil warm and then change the oil. I fill to spec and if it is near the low side, I fill it more until it is between high/low. If it leaks or burns oil, I'd aim for the high mark. These days my classics don't leak a drop and are rebuilt so I never worry about checking the oil between oil changes but if I were to, I'd check it cold. Newer vehicles I aim for high every time because of how much oil these newer engines seem to suck down, especially the 5.0 coyote.

In all the engines I've messed with, filling it to high and then having some oil drain down from the top end does not seem to impact anything, it's a small amount. I've overfilled engines and it was fine. Obviously you want to avoid the low side on engines but especially ones with timing chain tensioners and plastic guides. If you're worried about the oil draining down and causing it to read high cold, it will all work out once you start the engine and the oil goes back to laying on the top end.

[rjd2]

thanks-yea, i lived for many years with a mentality of "eh, close enough" on the dipstick. then i started getting real specific with it, so if the car wants to read at the 1/3 mark cold, close to full hot, i would do that, and found it extremely satisfying. that's the "why". thanks, signed, Mr Approaching 50 With Added OCD