5w30 to 5w40

[chill]

I was thinking about this. I have about a case of 5w40 left over from my VW's and i want to know if I can use it in the Jeep.

I understand that the flow of the 40 weight will be diffrent than the 30. But since the engine is a bit older (+ 100,000mi) I'm thinking that the "thicker" oil may fill in the gaps, cracks, crevesis etc. in the motor.

Is this just a stupid idea, or might I benifit from the different weight?

 

[67Customs]

I was thinking about this. I have about a case of 5w40 left over from my VW's and i want to know if I can use it in the Jeep.

I understand that the flow of the 40 weight will be diffrent than the 30. But since the engine is a bit older (+ 100,000mi) I'm thinking that the "thicker" oil may fill in the gaps, cracks, crevesis etc. in the motor.

Is this just a stupid idea, or might I benifit from the different weight?

First, if you aren't seeing any significan't oil loss in the miles between oil changes, there wouldn't be any benefit to using a higher weight just because it is over 100k miles. If there is no oil loss (or nominal loss), the 5W-30 is doing its job.

Second, if you feel the need to use this oil in the KJ, mix one quart of it with four quarts of 5W-30 in the next few changes.

It won't hurt to run one change of the 5W-40 to get rid of it, but I certainly wouldn't keep running 5W-40 just because the engine is older. Also, if you do decide to use the 5W-40 all at one time, I would use it during the hottest part of the year for your area.

Just my thoughts.

 

[chill]

Yeah, never mind. Seems like too much of a pain in the butt. I'll just get rid of it to a friend or something.

The motor is great as far as not leaking or loosing oil overtime. I guess i really don't have a need to use anything thicker.

Thanks, I appreciate the input.

 

[belvedere]

What climate do you live in?

 

[chill]

Mid Atlantic.

 

[belvedere]

You could certainly run the 5W40, and it may not be ideal (maybe slightly less mpg), but sure wouldn't hurt anything. If you feel uneasy about it, run it in the warmer months, or mix it 50/50 with 5W30 and run it year-round.

In the end, do what makes you comfortable. When you ask a question about oil, you're going to get a wide variety of opinions.