my truck is down a quart of oil. it uses 5w-20. i sent my wife up to get a quart and comes back saying that they did’nt have any 5w-20. so she gets a quart of 5w-30. is it a problem putting this quart in until i can get up to have the oil changed next week?

Put it in and don’t even think about it, no problem especially in the warmer weather. If it’s time to change the oil, why even bother adding a quart. If it’s not time to change the oil, just leave the 5w-30 in there until it’s time.

Nope! Not a problem.


What is your oil change interval now? 3k miles, 5k miles, 7k miles? With 1 fresh qt you added, extend your oil change for 1 more month. Maybe 2? Why go with too frequent oil changes?

So let’s see . . .

You check and correct the engine oil level

Then you reward yourself by deciding to change the oil one month later than originally scheduled.

You are not rewarding the engine by taking this approach

You should be regularly checking the fluid levels anyways

That is my take on the matter

If the oil is only down one quart, and you’re changing it next week, then why bother even adding that quart. Drive one quart low till you get it changed.


Then you reward yourself by deciding to change the oil one month later than originally scheduled.

Did the OP say that somewhere?

@JoeMario OP didn’t say that

Read what @Cavell posted

Now you will see why I posted what I did

I always keep a quart of oil in the trunk in case I need any on the road and keep a stock in the garage. Now how did you get your wife to go get some?

I have no idea how many miles or what kind of driving you are going to do until next week. The one quart of 5W-30 in the crankcase won’t make any difference. I, personally, would bring the oil up to the full mark even if I were changing oil next week. A couple of bucks for a quart of oil is, for me, is worth it to protect the engine. In fact, a quart of 10W-30 or even 10W-40 mixed with the 5W-20 won’t hurt a thing for at least a week.

I agree 100% with @Triedaq

The engine oil level should be correct at all times

And the oil change interval should be adhered to, regardless of how many quarts were added in between to maintain the correct oil level at all times.

This past Monday, when I checked the oil on my lawnmower, the dipstick showed that the oil was at the halfway mark on the safe range. I had used up the 30 weight and only had a half quart of 5W-30 on hand. I topped off the oil with that. It didn’t hurt a thing and I think it is critical to keep an air cooled engine crankcase full. I got through the yard Monday. I also had to mow today (Friday) – our grass is really thick with the rain we had. The oil was right up at the top of the dipstick.