Using 5w20 instead of 5w30 ... a conspiracy?

Many new car manufacturers advise using 5w20. I have heard they do this so they pay lower fees to the government, because thinner 5w20 allows gas mileage to be 1 or 2 mpg better. But, the thinner oil does not protect your engine nearly as well as 5w30 ... so your engine will blow up much sooner (after your warranty is expired, but sooner). But the auto manufacturers don't really care, because they don't want your engine to last 150,000 miles. They will sell less cars if everyone's car lasts for 10 years.

Has anyone else heard this?

Using 5w20 instead of 5w30 ... a conspiracy?antivirus software

I wouldn't say it is a conspiracy, but car companies are definitely specifying lower oil viscosities to report better gas mileage on their cars in advertising.

Today's engines as well as oils are much better than those made years ago and a thinner oil with the same protection as older thicker oils is common.

One of the main reasons 5W-20 was specified for your engine is to increase the CAFE (Corporate Average Fuel Economy) reported to the Federal Government. CAFE is the combined average fuel economy of all of a vehicle manufacturers product line. Minimum CAFE levels are specified by the Federal Government. In order for a vehicle manufacturer to continue selling profitable large trucks and SUVs, which typically have poor fuel mileage ratings, as compared to smaller cars, and still meet mandated CAFE requirements, they must also sell enough of the smaller cars which have much better fuel economy ratings to offset the poor fuel economy ratings of the larger vehicles. The change to a 5W-20 oil will allow and an auto companies overall CAFE to increase by a very small amount, typically in the tenths of a mile per gallon range. 5W-20 oil is a lighter viscosity than a 5W-30 oil and therefore has less internal engine frictional losses, or less drag on the crankshaft, pistons and valvetrain, which in turn promotes increased fuel economy. This increased fuel economy is virtually undetectable to the average motorist without the use of specialized engine monitoring and testing equipment under strictly controlled test track driving when compared to a 5W-30, 10W-30 or a 0W-30 viscosity motor oil.