Car filled a quart over

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Dec 8, 2015
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Location
Arkansas
So I was checking my Mazda 3 for oil. I checked it 3 times within a week and it was a quart low so I decided to add a quart. Decided to check it again today, about a week after doing this and its now showing a significant amount over, it looks as if it is a full quart over. Assuming this is a quart over (has 6 quarts in a 5 quart pan) should I drain the quart or just run it?
 
So I was checking my Mazda 3 for oil. I checked it 3 times within a week and it was a quart low so I decided to add a quart. Decided to check it again today, about a week after doing this and its now showing a significant amount over, it looks as if it is a full quart over. Assuming this is a quart over (has 6 quarts in a 5 quart pan) should I drain the quart or just run it?
Easier fix: go get yourself some appropriately sized clear tubing and suck it out through the dipstick tube. You can pull it out in small increments and get it exactly where you want it versus fumbling with a drain plug and taking out too much or too little. Third option would be just to replace the filter and see where your level lands.
 
I would very quickly remove the drain plug to allow an estimated quart to drain before reinstalling the plug. It's messy but effective.
When I check oil, I do it on a cold engine that sat overnight before starting it up. I think there's a possibility of an erroneous reading doing it warm.
 
To your original question, no I would not just run it, I’d drain it. I’ve run engines a quart over and some of them don’t like it very much...they’ll smoke as the oil is too high in the crankcase and forces it’s way into the combustion chamber. Smoke. Lots of smoke.

Funny thing though, with all the talk about piston soaks and freeing up stuck rings...maybe overfilling a crankcase with clean oil and an engine cleaner might not be a bad idea? Maybe it would it force its way up through those rings from the bottom.
 
My oil dipstick has five holes (that fill with oil) for determining the level.
The oil will NOT drain out of the holes overnight.

My procedure is:
1) remove dipstick and remove all oil from it.
2) reinstall and check level
 
This may not explain your discrepancy, but since it's come up in the comments. Check your owners manual to confirm proper oil level check procedures. Some manufacturers recommend a warm engine rather than cold for an oil level check, and the car's dipstick is designed for that (with the hashmarks/lines designed for taking into account the hot oil will have expanded versus a cold check)

The 2018 Mazda 3 4 door/5 door manual instructs a warm oil level check (not sure if this is the same as the 'hatch')
1. Be sure the vehicle is on a level surface.
2. Warm up the engine to normal operating temperature.
3. Turn it off and wait at least 5 minutes for the oil to return to the oil pan.
4. Pull out the dipstick, wipe it clean, and reinsert it fully

 
While I doubt that a single quart over would cause any real issues, I would probably drain an estimated quart from it, then check again. If it is under, add a little at a time and keep checking to get it to the right level. If it is still over, it will be so little that it won't matter.
 
This may not explain your discrepancy, but since it's come up in the comments. Check your owners manual to confirm proper oil level check procedures. Some manufacturers recommend a warm engine rather than cold for an oil level check, and the car's dipstick is designed for that (with the hashmarks/lines designed for taking into account the hot oil will have expanded versus a cold check)

The 2018 Mazda 3 4 door/5 door manual instructs a warm oil level check (not sure if this is the same as the 'hatch')
1. Be sure the vehicle is on a level surface.
2. Warm up the engine to normal operating temperature.
3. Turn it off and wait at least 5 minutes for the oil to return to the oil pan.
4. Pull out the dipstick, wipe it clean, and reinsert it fully

Same crappy non-sense in all Asian car owner's manuals that certainly leads to a silly situation exactly like the op's one. Oil will be either all over the dipstick or not completely back to oil pan.
Check oil cold before running engine in the morning.
 
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