5-20w vs. 5-30w oil

4 messages, Last post on Mar 23, 2008 at 8:48 PM

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#3 of 4 [re]5w20 vs. 5w30 by 52132 Dec 08, 2007 (5:24 pm)
I put 10w30 in mine, it provides better engine protection during hot weather [like in Florida]
#4 of 4 5W-20 vs 5W-30 by old89lsc Mar 23, 2008 (8:48 pm)
Around 2000, Ford (and perhaps, Honda) changed the engine oil specification from 5W-30 to 5W-20 for many vehicles. This was done without any actual engine mechanical changes. The reason was to improve fuel economy. The 5W-20 is less viscous (thinner) at operating temperature and, therefore, reduces the internal friction losses. Actually fuel economy gains (<5%) aren't likely to be noticed outside of the controlled environment of a lab. In other words, you and I can't tell the difference. The downside is that, given the same base stock, a 5W-20 oil will have less viscosity index improver in it, meaning that over time it may degrade to a less suitable oil more quickly than would a 5W-30 oil. The difficulty of the 5W-20 grade can partly be seen in that it is only offered in a synthetic blend formulation, typical base stocks would be dangerous to use in such an application. In the end, I prefer synthetic 5W-30 over 5W-20. I feel a lot safer with it and it doesn't cost more. In the hot summer time, I actually use 10W-30.