About a quart - have I ruined my car?

In short, no. If you read the answers on this similar question, even a gallon of extra oil generally won't ruin a car.

This is what I suggested and still recommend:

If the oil isn't hot, almost any sort of plastic tubing can be used for siphoning. It's easiest to go in via the dip stick.

Remember not to use the "suck start" siphoning method as you don't want a mouthful of oil. If you have a long enough piece of tubing, you can stick the excess down the dipstick tube, put your thumb over the end, pull out the slack (that is now full of oil) and you'll have an immediate siphon.

Also remember to siphon the oil back into the original container - you might as well keep it until you do need it.

It's not that big a deal. With an extra quart, most normal cars driven by normal people will just have slightly lower mileage due to pumping losses. Go ahead and get it back to the correct level, though: no need to waste gas or trouble your peace of mind.

About a quart - have I ruined my car?

In short, no. If you read the answers on this similar question, even a gallon of extra oil generally won't ruin a car.

This is what I suggested and still recommend:

If the oil isn't hot, almost any sort of plastic tubing can be used for siphoning. It's easiest to go in via the dip stick.

Remember not to use the "suck start" siphoning method as you don't want a mouthful of oil. If you have a long enough piece of tubing, you can stick the excess down the dipstick tube, put your thumb over the end, pull out the slack (that is now full of oil) and you'll have an immediate siphon.

Also remember to siphon the oil back into the original container - you might as well keep it until you do need it.

It's not that big a deal. With an extra quart, most normal cars driven by normal people will just have slightly lower mileage due to pumping losses. Go ahead and get it back to the correct level, though: no need to waste gas or trouble your peace of mind.