An oily question

I have a 2003 Impala which is just going past 106,000 miles on it. It appears that since my last oil change (about 3100 miles ago) i was down about 3/4 of quart of oil. I am not leaking anything that I can see. Is this ok/normal for an engine with that many miles and year to use 3/4 of quart of oil? Also, I know 5W30 was used on the oil change and all I had was 10W40 in my garage so I topped off with that, will that cause any issue?

This amount of oil use is perfectly normal and even great for a motor with 106,000 miles.
Manufacturers consider anything less than 1 quart every 1,000 miles to be acceptable. Some even consider greater oil usage acceptable. Your usage is excellent. And if you keep monitoring your fluids the way you obviously are, your engine will give you many, many more good miles.

The amount of 10W40 you added will not have any effect. The two will mix and you’ll have 5-1/2W31. I made that number up, by the way, as an estimate of what the two combined will be. Your engine will not know the difference. You get greater variation than that just due to environmentally-caused changes in engine temperature.

Congratulations. You’re doing great. And so is your engine.

3/4 quart in 3100 miles is fine, no problem at all for an engine with 106k miles. And 3/4 quart of 10W40 would not hurt anything, in my opinion.

Going 3,100 miles before checking the oil isn’t the best idea. Some cars would use three quarts in that period. You’ll want to check your oil more often, especially now that you know it’s burning or losing oil somehow.

Some brands of oil burn off at a higher rate than others. I’d not be concerned, especially if the temps are high and you are running the a/c a lot. Topping off with 10w-40 is fine in the summer. If you live in Minn, and it is January, that’s when you stick with the 5W-30.

Many folks with new cars wish their oil consumption was 3/4 quart in 3100 miles. Your 2003 Impala is doing just fine. Keep it well maintained so you don’t need to buy a new car. B/c if you do, if the comments from new car owners here are any indication, then you’re more likely to have oil consumption issues.

I check my oil weekly, but didn’t actually put any in till this time because it was still in the area on the stick that shows okay, only once it got done low on that area of the stick did I replace and thus had to use a 3/4 of a quart of oil.

Okay, I stand corrected. I’m glad you check it frequently.

If this were my car, I’d probably still top it off once it’s down by a half quart or so, just for the extra safety margin.

Make sure you pick up the correct oil to use from this point on. There’s no sense adding the wrong oil when you can just as easily add the correct one.

Think of it this way - you now have approximately 6W32 oil in your engine. Virtually an insignificant difference.