Different oil weight how bad?
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Instructor
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From: Hammond LA
Different oil weight how bad?
So I just noticed that yesterday I put 4 quarts of 5w-30 and 2 quarts of 15w-40 in my car how bad is that should I change out now or is it alright for 3k miles?
Team Owner
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From: Short Hills, NJ
While that weight is definitely not recommended it is mixed in with mostly the much thinner 5w-30. As long as the outside temps don't drop too much down there I think you should be fine until the next oil change. Just be sure to warm the car up completely before jumping on it at all (which one should do anyway regardless of oil weight). 
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Instructor
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From: Hammond LA
While that weight is definitely not recommended it is mixed in with mostly the much thinner 5w-30. As long as the outside temps don't drop too much down there I think you should be fine until the next oil change. Just be sure to warm the car up completely before jumping on it at all (which one should do anyway regardless of oil weight).
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Actually NOT a bad idea to put one quart of 15W-40 in at each oil change, same brand synthetic of course, to get a little extra zinc dithiophosphate in the lube.
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From: Missouri City, TX
While that weight is definitely not recommended it is mixed in with mostly the much thinner 5w-30. As long as the outside temps don't drop too much down there I think you should be fine until the next oil change. Just be sure to warm the car up completely before jumping on it at all (which one should do anyway regardless of oil weight).
I have done it myself on rare occasion. No biggie.
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From: Hammond LA