What grade to oil to use on my Honda Civic?

Look at the handbook.

The W value indicated the viscosity (thickness) of the oil. If you used 5 W your engine would wear away in a few hundred miles. Use the correct grade.

I have owned a 1995 honda concerto 1.6 for 12 years & have always used a good fully synthetic oil, It has covered 215 thousand trouble free miles & still uses little or no oil between 6000ml service's I think this gives you the answer.Good luck

Short answer: Use what your car's owner's manual recommends.

Longer answer:

What climate do you live in? The "w" in motor oil designations stands for "weight" and the number is a measure of the oil's viscosity. It has nothing to do with quality. A 5w motor oil has very low viscosity and might be appropriate to use in the middle of winter in Alaska. 40w motor oil has fairly high viscosity, appropriate to summer in Los Angeles.

There are also multi-weight oils that cover a range. 10w30 to 10w50 are commonly used in temperate or variable climates.

for best performance use only fully synthetic oil 5-40 or 5-50 multigrade, single grade oils are not suitable for modern engines

Look at you're owners manual. It should call for a 5W20 oil.

rice?Not white rice though, you must use only brown rice.