Hello,

Oops I mean Outlander ES. Although I know the model of the car doesn't make a difference.

I recently bought 5w-30 fully synthetic motor oil that is supposed to last 15,000 miles for my oil change (that's what it says on the box). The owners manual says that I should use 5w-20 for operating temperatures less than 100 degrees and that I should use 10W-30 for operating temperatures over 100 degrees. I'm assuming operating temperature means the temperature outside and not the temperature under the hood. Because the temperature under the hood can get really hot. So my question is:

Do you think 5W-30 will hurt my engine?

 

The "operating" temperature is the ambient temperatures the vehicle is used in and not the under the hood temperatures.

5w20 is a "energy saving" oil that runs a little thinner once the oil is heated up by the engine. This will provide you with better fuel mileage.
5w30 won't "hurt" your engine but you may see slightly higher fuel consumption because of the more work the engine has to do to move around the thicker oil when the engine heats up. Both have the same cold starting rating in the multiweight.

I can't see how your warranty would be affected since they indicate 10w30 in higher temperature climates but I'm sure they would try to give you a hard time if they saw 5w30 instead of 5w20 is used if you live in a cool climate.

This explains the multi-grades and why there are two numbers.
http://en.wikipedia.org/wiki/Motor_oil#Multi-grade

I wouldn't run extended oil change intervals (15,000 miles) until my warranty has expired. Which means don't buy the really expensive extended oils only to drain them out every 3,000 miles. You should still buy quality oils though!
If you are doing the work yourself buy the oil filter and drain plug crush ring right before you do the job so you have dates and parts on the bill. Hang onto those bills to prove your preventative maintenance was done.

At the end of the day you have to be comfortable with the oil you put in your vehicle. Mose people just use whatever is specified in the manual or on the filler cap. In our case 5w20.

Check out Bob is the Oil Guy forums for lots of talk on 5w20 vs 5w30. But remember those are often just people's opinions - just like mine above.

 

In Candada Mitsubishi just changed their recomended maintenance scheduale to 6 months or 12,000 km, even on conventional motor oil, on all 2005 and later models (except turbo models). I use mobil 1 5W20 in my Outlander.

 

Where did you get this. I just purchased a 2010 XLS and I am planing just that, i.e. Synthetic 5W20 every 6 months except for the first one at 3 months.
I would like to know the source as I think the dealership will moan.

 

I'm in Phoenix where temps often get over 100. My dealer uses 10W-30 Valvoline. Also because of the hot weather, I follow the severe maintenance schedule which calls for oil changes at 3 months/3750 miles.

 

The dealership is who told me. Now the service intervals have gone back to 3 months 6,000 km because service departments have complained about lost business. This has nothing to do with the service a new Mitsubishi needs. I contacted Mitsubishi Customer Service and after pushing the issue they told me that if I do an oil change every 12,000 km with synthetic oil I will not have any warranty issues, but they would not put it in writing.

The best thing to do it let the OEM know you are un happy with the 3 month 6,000 km interval. They will listen.