My 2006 3.7 liter v6 in my jeep liberty is spec'ed for 5w30. In 2007 this engine in the liberty application became spec'ed for 5w20. I know a lot of people here say to "go with what the manual says." I am just curious if this is because people are just taking into consideration warranty issues, or if they feel what is in the manual is just plain best for the year that engine was produced. If so, does that mean that the '07 and up engines spec'ed for 5w20 have actually been changed from the 5w30 engines? What kind of changes could they have possibly done that would require the thin stuff? This has always confused me, so thanks for your input.
Oil spec question
- Thread starter hooperswish1
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A lot of manufacturers have gone to 5W-20 for CAFÉ (Corporate Average Fuel Economy) fuel economy reasons. 5W-20 can maybe gain somewhere ~ 0.6 - 1.0 % increase in fuel economy over the 30 weights. So the manufacturer's ship the auto's with 5W-20 and get the EPA gas mileage certification with 5W-20 in the crankcase instead of a 30 weight (boost average fuel economy rating for vehicles). But the EPA said to the manufacturer's, if you use 5W-20 to certify the gas mileage on your vehicles, then you have to clearly recommend and specify that weight oil.
Doubtful any change was made to the engines with the move to specify 5W-20 over 5W30. I have a stash of 5w30. If any new vehicle I buy specifies 5W-20 -- too bad, it's going to be using 5w30.
Doubtful any change was made to the engines with the move to specify 5W-20 over 5W30. I have a stash of 5w30. If any new vehicle I buy specifies 5W-20 -- too bad, it's going to be using 5w30.
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